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1. Inter-Cation Charge Transfer Mediated Antiferromagnetism in Co$_{1+x}$Ir$_{2-x}$S$_4$

Author

Ji, Liang-Wen, Wu, Si-Qi, Li, Bai-Zhuo, Yang, Wu-Zhang, Song, Shi-Jie, Liu, Yi, Li, Jing, Ren, Zhi, and Cao, Guang-Han

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

The antiferromagnetism in transition metal compounds is mostly mediated by the bridging anions through a so-called superexchange mechanism. However, in materials like normal spinels $AB_2X_4$ with local moments only at the $A$ site, such an anion-mediated superexchange needs to be modified. Here we report a new spinel compound Co$_{1+x}$Ir$_{2-x}$S$_4$ ($x$ = 0.3). The physical property measurements strongly suggest an antiferromagnetic-like transition at 292 K in the Co($A$) diamond sublattice. The first-principle calculations reveal that the nearest-neighbor Co($A$) spins align antiferromagnetically with an ordered magnetic moment of 1.67 $\mu_\mathrm{B}$, smaller than the expected $S = 3/2$ for Co$^{2+}$. In the antiferromagnetic state, there exists an inter-cation charge-transfer gap between the non-bonding Ir-$t_\mathrm{2g}$ orbitals at the valence band maximum and the Co-S antibonding molecular orbitals at the conduction band minimum. The small charge transfer energy significantly enhances the virtual hopping between these two states, facilitating a robust long-range superexchange interaction between two neighboring CoS$_4$ complexes, which accounts for the high N\'{e}el temperature in Co$_{1+x}$Ir$_{2-x}$S$_4$. This inter-cation charge transfer mediated magnetic interaction expands the traditional superexchange theory, which could be applicable in complex magnetic materials with multiple cations., Comment: 10 pages, 7 figures

Published
2024
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2. Superconductivity in kagome metal ThRu3Si2

Author

Liu, Yi, Li, Jing, Yang, Wu-Zhang, Lu, Jia-Yi, Cao, Bo-Ya, Li, Hua-Xun, Chai, Wan-Li, Wu, Si-Qi, Li, Bai-Zhuo, Sun, Yun-Lei, Jiao, Wen-He, Cao, Wang, Xu, Xiao-Feng, Zhi, Ren, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity
Abstract

We report the physical properties of ThRu$_3$Si$_2$ featured with distorted Ru kagome lattice. The combined experiments of resistivity, magnetization and specific heat reveal bulk superconductivity with $T_{\rm{c}}$ = 3.8 K. The specific heat jump and calculated electron-phonon coupling indicate a moderate coupled BCS superconductor. In comparison with LaRu$_3$Si$_2$, the calculated electronic structure in ThRu$_3$Si$_2$ shows an electron-doping effect with electron filling lifted from 100 meV below flat bands to 300 meV above it. This explains the lower superconducting transition temperature and weaker electron correlations observed in ThRu$_3$Si$_2$. Our work suggests the $T_{\rm{c}}$ and electronic correlations in kagome superconductor could have intimate connection with the flat bands., Comment: 7 pages, 5 figures

Published
2024
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3. Superconductivity and Charge-density-wave-like Transition in Th2Cu4As5

Author

Duan, Qing-Chen, Liu, Shao-Hua, Li, Bai-Zhuo, Meng, Jiao-Jiao, Yang, Wu-Zhang, Liu, Yi, Lin, Yi-Qiang, Wu, Si-Qi, Lu, Jia-Yi, Bao, Jin-Ke, Xiao, Yu-Sen, Zhao, Xin-Yu, Mei, Yu-Xue, Sun, Yu-Ping, Yu, Dan, Tan, Shu-Gang, Jing, Qiang, Zhong, Rui-Dan, Chen, Yong-Liang, Zhao, Yong, Ren, Zhi, Wang, Cao, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity
Abstract

We report the synthesis, crystal structure, and physical properties of a novel ternary compound, Th$_2$Cu$_4$As$_5$. The material crystallizes in a tetragonal structure with lattice parameters $a=4.0716(1)$ {\AA} and $c=24.8131(4)$ {\AA}. Its structure can be described as an alternating stacking of fluorite-type Th$_2$As$_2$ layers with antifluorite-type double-layered Cu$_4$As$_3$ slabs. The measurement of electrical resistivity, magnetic susceptibility and specific heat reveals that Th$_2$Cu$_4$As$_5$ undergoes bulk superconducting transition at 4.2 K. Moreover, all these physical quantities exhibit anomalies at 48 K, where the Hall coefficient change the sign. These findings suggest a charge-density-wave-like (CDW) transition, making Th$_2$Cu$_4$As$_5$ a rare example for studying the interplay between CDW and superconductivity., Comment: 11 pages, 6 figures, and 1 table

Published
2023

4. Superconductivity under pressure in a chromium-based kagome metal

Author

Liu, Yi, Liu, Zi-Yi, Bao, Jin-Ke, Yang, Peng-Tao, Ji, Liang-Wen, Wu, Si-Qi, Shen, Qin-Xin, Luo, Jun, Yang, Jie, Liu, Ji-Yong, Xu, Chen-Chao, Yang, Wu-Zhang, Chai, Wan-Li, Lu, Jia-Yi, Liu, Chang-Chao, Wang, Bo-Sen, Jiang, Hao, Tao, Qian, Ren, Zhi, Xu, Xiao-Feng, Cao, Chao, Xu, Zhu-An, Zhou, Rui, Cheng, Jin-Guang, and Cao, Guang-Han

Published
2024
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5. YOLOv8-EMSC: A lightweight fire recognition algorithm for large spaces

Author

Deng Li, Tan Yang, Zhou Jin, Wu Si-qi, and Liu Quan-yi

Subjects
Fire detection, Large space, Lightweight, YOLOv8, YOLOv8-EMSC, Risk in industry. Risk management, HD61
Abstract

Stringent fire prevention requirements are imperative in expansive environments. Fire detection in diverse large-scale settings typically relies on sensor-based or AI-driven target detection methods. Traditional fire detectors often suffer from false alarms and missed detections, failing to meet the fire safety requirements of large-scale structures. Many existing target detection algorithms are characterized by substantial model sizes. Some detection terminals in large structures face challenges deploying these models due to constrained computational resources. To address this issue, we propose a lightweight model, YOLOv8-EMSC, derived from YOLOv8n. The incorporation of C2f_EMSC, replacing the C2f module, significantly reduces the model parameters in the enhanced YOLOv8-EMSC model compared to YOLOv8n, thereby enhancing model inference speed. Extensive testing and validation using a custom-built large-scale infrared fire dataset demonstrates a 9.6 % reduction in parameters compared to the baseline model for YOLOv8-EMSC, achieving an average precision of 95.6 %, surpassing both the baseline and mainstream models and significantly enhancing fire detection accuracy in expansive environments.

Published
2024
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6. Retinoblastoma with and without Extraocular Tumor Extension: A Global Comparative Study of 3435 Patients

Author

Fabian, Ido Didi, Abdallah, Elhassan, Abdullahi, Shehu U., Abdulqader, Rula A., Abdulrahaman, Aminatu A., Abouelnaga, Sherif, Ademola-Popoola, Dupe S., Adio, Adedayo, Afifi, Mahmoud A., Afshar, Armin R., Aggarwal, Priyanka, Aghaji, Ada E., Ahmad, Alia, Akib, Marliyanti N.R., Akinsete, Adeseye M., Al Harby, Lamis, Al Mesfer, Saleh A., Al Ani, Mouroge H., Portabella, Silvia Alarcón, Al-Badri, Safaa A.F., Alcasabas, Ana Patricia A., Al-Dahmash, Saad A., Alejos, Amanda, Alemany-Rubio, Ernesto, Alfa Bio, Amadou I., Carreras, Yvania Alfonso, Al-Haddad, Christiane E., Al-Hussaini, Hamoud H.Y., Ali, Amany M., Alia, Donjeta B., Al-Jadiry, Mazin F., Al-Jumaly, Usama, Alkatan, Hind M., All-Eriksson, Charlotta, Al-Mafrachi, Ali A.R.M., Almeida, Argentino A., Alsawidi, Khalifa M., Al-Shaheen, Athar A.S.M., Al-Shammary, Entissar H., Amankwaa-Frempong, Doreen, Amiruddin, Primawita O., Armytasari, Inggar, Astbury, Nicholas J., Atalay, Hatice T., Ataseven, Eda, Atchaneeyasakul, La-ongsri, Atsiaya, Rose, Autrata, Rudolf, Balaguer, Julia, Balayeva, Ruhengiz, Barranco, Honorio, Bartoszek, Paulina, Bartuma, Katarina, Bascaran, Covadonga, Bechrakis, Nikolaos E., Popovic, Maja Beck, Begimkulova, Ainura S., Benmiloud, Sarra, Berete, Rokia C., Berry, Jesse L., Bhaduri, Anirban, Bhat, Sunil, Bhattacharyya, Arpita, Biewald, Eva M., Binkley, Elaine, Blum, Sharon, Bobrova, Nadia, Boldt, H. Culver, Bonanomi, Maria Teresa B.C., Bouda, Gabrielle C., Bouguila, Hédi, Brennan, Rachel C., Brichard, Bénédicte G., Buaboonnam, Jassada, Budiongo, Aléine, Burton, Matthew, Calderón-Sotelo, Patricia, Calle Jara, Doris A., Camuglia, Jayne E., Cano, Miriam R., Capra, Michael, Caspi, Shani, Cassoux, Nathalie, Castela, Guilherme, Castillo, Luis, Català-Mora, Jaume, Caviedes, Isabel, Chandramohan, Arthika, Chantada, Guillermo L., Chaudhry, Shabana, Chawla, Bhavna, Chen, Wensi, Chiwanga, Faraja S., Chuluunbat, Tsengelmaa, Cieslik, Krzysztof, Clark, Antony, Cockcroft, Ruellyn L., Comsa, Codruta, Correa Llano, Maria G., Corson, Timothy W., Couitchere, Line, Cowan-Lyn, Kristin E., Csóka, Monika, Dangboon, Wantanee, Das, Anirban, Das, Pranab, Das, Sima, Davanzo, Jacquelyn M., Davidson, Alan, De Francesco, Sonia, De Potter, Patrick, Delgado, Karina Q., Demirci, Hakan, Desjardins, Laurence, Diaz Coronado, Rosdali Y., Dimaras, Helen, Dodgshun, Andrew J., Donato Macedo, Carla R., Dragomir, Monica D., Du, Yi, Du Bruyn, Magritha, Du Plessis, Johannes P., Dudeja, Gagan, Eerme, Katrin, Eka Sutyawan, I Wayan, El Kettani, Asmaa, Elbahi, Amal M., Elder, James E., Elhaddad, Alaa M., Elhassan, Moawia M.A., Elzembely, Mahmoud M., Ericksen, Connor, Essuman, Vera A., Evina, Ted Grimbert A., Ezegwui, Ifeoma R., Fadoo, Zehra, Fandiño, Adriana C., Faranoush, Mohammad, Fasina, Oluyemi, Fernández, Delia D.P.G., Fernández-Teijeiro, Ana, Foster, Allen, Frenkel, Shahar, Fu, Ligia D., Fuentes-Alabi, Soad L., Garcia, Juan L., Aldana, David García, Garcia Pacheco, Henry N., Geel, Jennifer A., Ghassemi, Fariba, Girón, Ana V., Goenz, Marco A., Gold, Aaron S., Golberg, Hila, Gole, Glen A., Gomel, Nir, Gonzalez, Efren, Perez, Graciela Gonzalez, González-Rodríguez, Liudmira, Gorfine, Malka, Graells, Jaime, Gregersen, Pernille A., Grigorovski, Nathalia D.A.K., Guedenon, Koffi M., Gunasekera, D Sanjeeva, Gündüz, Ahmet K., Gupta, Himika, Gupta, Sanjiv, Gupta, Vineeta, Hadjistilianou, Theodora, Hamel, Patrick, Hamid, Syed A., Hamzah, Norhafizah, Hansen, Eric D., Harbour, J William, Hartnett, M. Elizabeth, Hasanreisoglu, Murat, Hassan, Sadiq, Hassan, Shadab, Hautz, Wojciech, Haydar, Huda A., Hederova, Stanislava, Hessissen, Laila, Lalaina, Hoby, Hongeng, Suradej, Hordofa, Diriba F., Hubbard, G. Baker, Hummlen, Marlies, Husakova, Kristina, Hussein Al-Janabi, Allawi N., Ibanga, Affiong A., Ida, Russo, Ilic, Vesna R., Islamov, Ziyavuddin, Jairaj, Vivekaraj, Janjua, Teyyeb A., Jeeva, Irfan, Ji, Xunda, Jo, Dong Hyun, Jones, Michael M., Amani Kabesha, Theophile B., Kabore, Rolande L., Kaliki, Swathi, Kalinaki, Abubakar, Kamsang, Pius, Kantar, Mehmet, Kapelushnik, Noa, Kardava, Tamar, Kebudi, Rejin, Keomisy, Jonny, Kepak, Tomas, Ketteler, Petra, Khan, Zohora J., Khaqan, Hussain A., Khetan, Vikas, Khodabande, Alireza, Khotenashvili, Zaza, Kim, Jonathan W., Kim, Jeong Hun, Kiratli, Hayyam, Kivelä, Tero T., Klett, Artur, Koç, Irem, Kosh Komba Palet, Jess Elio, Krivaitiene, Dalia, Kruger, Mariana, Kulvichit, Kittisak, Kuntorini, Mayasari W., Kyara, Alice, Lam, Geoffrey C., Larson, Scott A., Latinović, Slobodanka, Laurenti, Kelly D., Lavi, Yotam, Groznik, Alenka Lavric, Leverant, Amy A., Li, Cairui, Li, Kaijun, Limbu, Ben, Liu, Chun-Hsiu, Long, Quah Boon, López, Juan P., Lukamba, Robert M., Luna-Fineman, Sandra, Lutfi, Delfitri, Lysytsia, Lesia, Madgar, Shiran, Magrath, George N., Mahajan, Amita, Maitra, Puja, Maka, Erika, Makimbetov, Emil K., Maktabi, Azza M.Y., Maldonado, Carlos, Mallipatna, Ashwin, Manudhane, Rebecca, Manzhuova, Lyazat, Begue, Nieves Martín, Masud, Sidra, Matende, Ibrahim O., Mattosinho, Clarissa C.D.S., Matua, Marchelo, Mayet, Ismail, Mbumba, Freddy B., McKenzie, John D., Mehrvar, Azim, Mengesha, Aemero A., Menon, Vikas, Mercado, Gary John V.D.D., Mets, Marilyn B., Midena, Edoardo, Miller, Audra, Mishra, Divyansh K.C., Mndeme, Furahini G., Mohamedani, Ahmed A., Mohammad, Mona T., Moll, Annette C., Montero, Margarita M., Moreira, Claude, Mruthyunjaya, Prithvi, Msina, Mchikirwa S., Msukwa, Gerald, Mudaliar, Sangeeta S., Muhammad, Hassan, Muma, Kangwa I., Munier, Francis L., Murray, Timothy G., Musa, Kareem O., Mushtaq, Asma, Musika, Anne A., Mustak, Hamzah, Mustapha, Tajudeen, Muyen, Okwen M., Myezo, Khumo H., Naidu, Gita, Naidu, Natasha, Nair, Akshay Gopinathan, Natarajan, Sundaram, Naumenko, Larisa, Ndoye Roth, Paule Aïda, Nency, Yetty M., Neroev, Vladimir, Ng, Yvonne, Nikitovic, Marina, Nkanga, Elizabeth D., Nkumbe, Henry E., Numbi, Marcel N., Nummi, Kalle, Nuruddin, Murtuza, Nyaywa, Mutale, Nyirenda, Chinsisi, Obono-Obiang, Ghislaine, Oliver, Scott C.N., Ooporto, Joaquin, Ortega-Hernández, Miriam, Oscar, Alexander, Ossandon, Diego, Pagarra, Halimah, Paintsil, Vivian, Paiva, Luisa, Palanivelu, Mahesh Shanmugam, Papyan, Ruzanna, Parrozzani, Raffaele, Pascual Morales, Claudia R., Paton, Katherine E., Pe'er, Jacob, Calvo, Jesús Peralta, Perić, Sanja, Pham, Chau T.M., Philbert, Remezo, Plager, David A., Pochop, Pavel, Polania, Rodrigo A., Polyakov, Vladimir, Ponce, Jimena, Qadir, Ali O., Qayyum, Seema, Qian, Jiang, Rahman, Ardizal, Rajkarnikar, Purnima, Ramanjulu, Rajesh, Ramasubramanian, Aparna, Ramirez-Ortiz, Marco A., Randhawa, Jasmeen K., Raobela, Léa, Rashid, Riffat, Reddy, M. Ashwin, Renner, Lorna A., Reynders, David, Ribadu, Dahiru, Ritter-Sovinz, Petra, Rogowska, Anna, Rojanaporn, Duangnate, Romero, Livia, Roy, Soma R., Saab, Raya H., Saakyan, Svetlana, Sabhan, Ahmed H., Sagoo, Mandeep S., Said, Azza M.A., Saiju, Rohit, Salas, Beatriz, San Román Pacheco, Sonsoles, Sánchez, Gissela L., Sanchez Orozco, Alma Janeth, Sayalith, Phayvanh, Scanlan, Trish A., Schwab, Christoph, Sedaghat, Ahad, Seth, Rachna, Sgroi, Mariana, Shah, Ankoor S., Shakoor, Shawkat A., Sharma, Manoj K., Sherief, Sadik T., Shields, Carol L., Sia, David, Noorani Siddiqui, Sorath, Sidi cheikh, Sidi, Silva, Sónia, Singh, Arun D., Singh, Usha, Singha, Penny, Sitorus, Rita S., Skalet, Alison H., Soebagjo, Hendrian D., Sorochynska, Tetyana, Ssali, Grace, Stacey, Andrew W., Staffieri, Sandra E., Stahl, Erin D., Steinberg, David M., Stones, David K., Strahlendorf, Caron, Coleoni Suarez, Maria Estela, Sultana, Sadia, Sun, Xiantao, Superstein, Rosanne, Supriyadi, Eddy, Surukrattanaskul, Supawan, Suzuki, Shigenobu, Svojgr, Karel, Sylla, Fatoumata, Tamamyan, Gevorg, Tan, Deborah, Tandili, Alketa, Tang, Jing, Tarrillo Leiva, Fanny F., Tashvighi, Maryam, Tateshi, Bekim, Teh, Kok Hoi, Tehuteru, Edi S., Teixeira, Luiz F., Pompe, Manca Tekavcic, Thawaba, Abdullah Dahan M., Theophile, Tuyisabe, Toledano, Helen, Trang, Doan L., Traoré, Fousseyni, Tripathy, Devjyoti, Tuncer, Samuray, Tyau-Tyau, Harba, Umar, Ali B., Unal, Emel, Uner, Ogul E., Urbak, Steen F., Ushakova, Tatiana L., Usmanov, Rustam H., Valeina, Sandra, Valente, Paola, van Hoefen Wijsard, Milo, Vasquez Anchaya, Jacqueline Karina, Vaughan, Leon O., Veleva-Krasteva, Nevyana V., Verma, Nishant, Victor, Andi A., Viksnins, Maris, Villacís Chafla, Edwin G., Villegas, Victor M., Vishnevskia-Dai, Victoria, Waddell, Keith, Wali, Amina H., Wang, Yi-Zhuo, Wangtiraumnuay, Nutsuchar, Wetter, Julie A., Riono, Widiarti P., Wilson, Matthew W., Wime, Amelia D.C., Wiwatwongwana, Atchareeya, Wiwatwongwana, Damrong, Dod, Charlotte Wolley, Wong, Emily S., Wongwai, Phanthipha, Wu, Si-qi, Xiang, Daoman, Xiao, Yishuang, Xu, Bing, Xue, Kang, Yaghy, Antonio, Yam, Jason C., Yang, Huasheng, Yanga, Jenny M., Yaqub, Muhammad A., Yarovaya, Vera A., Yarovoy, Andrey A., Ye, Huijing, Yee, Roberto I., Yousef, Yacoub A., Yuliawati, Putu, López, Arturo M., Zein, Ekhtelbenina, Zhang, Yi, Zhilyaeva, Katsiaryna, Zia, Nida, Ziko, Othman A.O., Zondervan, Marcia, Schlüter, Sabrina, Bowman, Richard, and Vempuluru, Vijitha S.

Published
2025
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7. WannSymm: A symmetry analysis code for Wannier orbitals

Author

Zhi, Guo-Xiang, Xu, Chenchao, Wu, Si-Qi, Ning, Fanlong, and Cao, Chao

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

We derived explicit expressions of symmetry operators on Wannier basis, and implemented these operators in WannSymm software. Based on this implementation, WannSymm can i) symmetrize the real-space Hamiltonian output from Wannier90 code, ii) generate symmetry operators of the little group at a specific k-point, and iii) perform symmetry analysis for Wannier band structure. In general, symmetrized Hamiltonians yield improved results compared with the original ones when they are employed for nodal structure searching, surface Green's function calculations, and other model calculations., Comment: 22 pages, 7 figures, WannSymm code can be downloaded from https://github.com/ccao/WannSymm ; typos corrected, references added

Published
2021
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8. Synthesis, structure and properties of layered phosphide nitrides $Ak$Th$_2$Mn$_4$P$_4$N$_2$ ($Ak$ = Rb, Cs)

Author

Li, Bai-Zhuo, Wu, Si-Qi, Wang, Zhi-Cheng, Wang, Cao, and Cao, Guang-Han

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

We report the design, synthesis, structure, and properties of two complex layered phosphide nitrides, $Ak$Th$_2$Mn$_4$P$_4$N$_2$ ($Ak$ = Rb, Cs), which contain anti-fluorite-type [Mn$_2$P$_2$] bilayers separated by fluorite-type [Th2N2] layers as a result of the intergrowth between AkMn$_2$P$_2$ and ThMnPN. The new compounds are featured with an intrinsic hole doping associated with the interlayer charge transfer and a built-in chemical pressure from the [Th$_2$N$_2$] layers, both of which are reflected by the changes in the lattice and the atomic position of phosphorus. The measurements of magnetic susceptibility, electrical resistivity, and specific heat indicate existence of local moments as well as itinerant electrons in relation with d-p hybridizations. The expected dominant antiferromagnetic interactions with enhanced d-p hybridizations were demonstrated by the first-principles calculations only when additional Coulomb repulsions are included. The density of states at the Fermi level derived from the specific-heat analysis are 3.5 and 7.5 times of the calculated ones for Ak = Rb and Cs, respectively, suggesting strong electron correlations in the title compounds., Comment: 12 pages, 5 figures, 3 tables; Supporting information available on request

Published
2021
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9. Magnetic and superconducting phase diagram of Eu(Fe$_{1-x}$Ni$_{x}$)As$_{2}$

Author

Liu, Ya-Bin, Liu, Yi, Cui, Yan-Wei, Wu, Si-Qi, Ren, Zhi, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

We report the Ni-doping effect on magnetism and superconductivity (SC) in an Eu-containing 112-type system Eu(Fe$_{1-x}$Ni$_{x})$As$_{2}$ ($0\leq x\leq 0.15$) by the measurements of resistivity, magnetization, and specific heat. The undoped EuFeAs$_2$ undergoes a spin-density-wave (SDW) transition at $T_\mathrm{SDW}\sim$ 105 K in the Fe sublattice and a magnetic ordering at $T_\mathrm{m}\sim$ 40 K in the Eu sublattice. Complex Eu-spin magnetism is manifested by a spin-glass reentrance at $T_\mathrm{SG}\sim$ 15 K and an additional spin reorientation at $T_\mathrm{SR}\sim$ 7 K. With Ni doping, the SDW order is rapidly suppressed, and SC emerges in the Ni-doping range of 0.01 $\leq x\leq$ 0.1 where a maximum of the superconducting transition temperature $T_\mathrm{c}^{\mathrm{max}}=$ 17.6 K shows up at $x$ = 0.04. On the other hand, $T_\mathrm{m}$ decreases very slowly, yet $T_\mathrm{SG}$ and $T_\mathrm{SR}$ hardly change with the Ni doping. The phase diagram has been established, which suggests a very weak coupling between SC and Eu spins. The complex Eu-spin magnetism is discussed in terms of the Ruderman-Kittel-Kasuya-Yosida interactions mediated by the conduction electrons from both layers of FeAs and As surrounding Eu$^{2+}$ ions., Comment: 10 pages, 7 figures; supplemental materials available on request

Published
2021
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11. Lifshitz Transition and Nontrivial H-Doping Effect in Cr-based Superconductor KCr$_3$As$_3$H$_x$

Author

Wu, Si-Qi, Cao, Chao, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

We report the first-principles study on the H-intercalated Cr-based superconductor KCr$_3$As$_3$H$_x$. Our results show a paramagnetic ground state for KCr$_3$As$_3$H. The electronic structure consists of two quasi-one-dimensional (Q1D) Fermi-surfaces and one 3D Fermi-surface which are mainly contributed by Cr-d$_{z^2}$, d$_{x^2-y^2}$ and d$_{xy}$ orbitals. The bare electron susceptibility shows a $\Gamma$-centered imaginary peak, indicating possible ferromagnetic spin fluctuations. Upon moderate hole doping, the system undergoes a Lifshitz transition, which may enhance the Q1D feature of the system. The Bader charge analysis and electron localization functions reveal a strong bonding nature of hydrogen in KCr$_3$As$_3$H, which results in a nontrivial electron doping in KCr$_3$As$_3$H.

Published
2019
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12. BaTh$_2$Fe$_4$As$_4$(N$_{0.7}$O$_{0.3}$)$_2$: An Iron-Based Superconductor Stabilized by Inter-Block-Layer Charge Transfer

Author

Shao, Ye-Ting, Wang, Zhi-Cheng, Li, Bai-Zhuo, Wu, Si-Qi, Wu, Ji-Feng, Ren, Zhi, Qiu, Su-Wen, Rao, Can, Wang, Cao, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

Recently, An electron-doped 12442-type iron-based superconductor BaTh$_2$Fe$_4$As$_4$(N$_{0.7}$O$_{0.3}$)$_2$ has been successfully synthesized with high-temperature solid-state reactions on basis of a structural design. The inter-block-layer charge transfer between the constituent units of "BaFe$_2$As$_2$" and "ThFeAsN$_{0.7}$O$_{0.3}$" was found to be essential to stabilize the target compound. Dominant electron-type conduction and bulk superconducting transition at ~22 K were demonstrated., Comment: 16 pages in total. 5 figures, 1 table (main article); 6 figures, 3 tables (Supporting Information)

Published
2019
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15. Giant anisotropy in superconducting single crystals of CsCa$_2$Fe$_4$As$_4$F$_2$

Author

Wang, Zhi-Cheng, Liu, Yi, Wu, Si-Qi, Shao, Ye-Ting, Ren, Zhi, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity
Abstract

CsCa$_2$Fe$_4$As$_4$F$_2$ is a newly discovered iron-based superconductor with $T_\mathrm{c}\sim$ 30 K containing double Fe$_2$As$_2$ layers that are separated by insulating Ca$_2$F$_2$ spacer layers. Here we report the transport and magnetization measurements on CsCa$_2$Fe$_4$As$_4$F$_2$ single crystals grown for the first time using the self flux of CsAs. We observed a huge resistivity anisotropy $\rho_c(T)/\rho_{ab}(T)$, which increases with decreasing temperature, from 750 at 300 K to 3150 at 32 K. The $\rho_c(T)$ data exhibit a non-metallic behavior above $\sim$140 K, suggesting an incoherent electronic state at high temperatures due to the dimension crossover. The superconducting onset transition temperature in $\rho_{ab}$ is 0.7 K higher than that in $\rho_c$, suggesting two-dimensional (2D) superconducting fluctuations. The lower and upper critical fields also show an exceptional anisotropy among iron-based superconductors. The $H_{c1}^\bot(T)$ data are well fitted using the model with two $s$-wave-like superconducting gaps, $\Delta_1(0)=6.75$ meV and $\Delta_2(0)=2.32$ meV. The inter-plane coherence length $\xi_c(0)$ is $3.6$ \AA, remarkably smaller than the distance between conducting layers (8.6 \AA), consolidating the 2D nature in the title material., Comment: 8 pages, 5 figures, 1 Table

Published
2018
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16. Weak metal-metal transition in the vanadium oxytelluride Rb$_{1-\delta}$V$_2$Te$_2$O

Author

Ablimit, Abduweli, Sun, Yun-Lei, Jiang, Hao, Wu, Si-Qi, Liu, Ya-Bin, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

We report the synthesis, crystal structure, physical properties, and first-principles calculations of a vanadium-based oxytelluride Rb$_{1-\delta}$V$_2$Te$_2$O ($\delta\approx0.2$). The crystal structure bears two-dimensional V$_2$O square nets sandwiched with tellurium layers, mimicking the structural motifs of cuprate and iron-based superconductors. The material exhibits metallic conductivity with dominant hole-type charge carriers. A weak metal-to-metal transition takes place at $\sim$100 K, which is conformably characterized by a slight kink/hump in the electrical resistivity, jumps in the Hall and Seebeck coefficients, a minute drop in the magnetic susceptibility, and a small peak in the heat capacity. Neither Bragg-peak splitting nor superlattice reflections can be detected within the resolution of conventional x-ray diffractions. The band-structure calculations show that V-3$d$ orbitals dominate the electronic states at around Fermi energy where a $d_{yz}/d_{xz}$ orbital polarization shows up. There are three Fermi-surface sheets that seem unfavorable for nesting. Our results suggest an orbital or spin-density-wave order for the low-temperature state and, upon suppression of the competing order, emergence of superconductivity could be expected., Comment: 11 pages, 2 tables, and 9 figures

Published
2018
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17. The Global Retinoblastoma Outcome Study: a prospective, cluster-based analysis of 4064 patients from 149 countries

Author

Fabian, Ido Didi, Abdallah, Elhassan, Abdullahi, Shehu U, Abdulqader, Rula A, Abdulrahaman, Aminatu A, Abouelnaga, Sherif, Ademola-Popoola, Dupe S, Adio, Adedayo, Afifi, Mahmoud A, Afshar, Armin R, Aggarwal, Priyanka, Aghaji, Ada E, Ahmad, Alia, Akib, Marliyanti NR, Akinsete, Adeseye, Al Harby, Lamis, Al Mesfer, Saleh, Al Ani, Mouroge H, Alarcón Portabella, Silvia, Al-Badri, Safaa AF, Alcasabas, Ana Patricia A, Al-Dahmash, Saad A, Alejos, Amanda, Alemany-Rubio, Ernesto, Alfa Bio, Amadou I, Alfonso Carreras, Yvania, Al-Haddad, Christiane E, Al-Hussaini, Hamoud HY, Ali, Amany M, Alia, Donjeta B, Al-Jadiry, Mazin F, Al-Jumaily, Usama, Alkatan, Hind M, All-Eriksson, Charlotta, Al-Mafrachi, Ali ARM, Almeida, Argentino A, Alsawidi, Khalifa M, Al-Shaheen, Athar ASM, Al-Shammary, Entissar H, Amankwaa-Frempong, Doreen, Amiruddin, Primawita O, Armytasari, Inggar, Astbury, Nicholas J, Atalay, Hatice T, Ataseven, Eda, Atchaneeyasakul, La-ongsri, Atsiaya, Rose, Autrata, Rudolf, Balaguer, Julia, Balayeva, Ruhengiz, Barranco, Honorio, Bartoszek, Paulina, Bartuma, Katarina, Bascaran, Covadonga, Bechrakis, Nikolaos E, Beck Popovic, Maja, Begimkulova, Ainura S, Benmiloud, Sarra, Berete, Rokia C, Berry, Jesse L, Bhaduri, Anirban, Bhat, Sunil, Bhattacharyya, Arpita, Biewald, Eva M, Binkley, Elaine, Blum, Sharon, Bobrova, Nadia, Boldt, H.C., Bonanomi, Maria Teresa BC, Bouda, Gabrielle C, Bouguila, Hédi, Brennan, Rachel C, Brichard, Bénédicte G, Buaboonnam, Jassada, Budiongo, Aléine, Burton, Matthew J, Calderón-Sotelo, Patricia, Calle Jara, Doris A, Camuglia, Jayne E, Cano, Miriam R, Capra, Michael, Caspi, Shani, Cassoux, Nathalie, Castela, Guilherme, Castillo, Luis, Català-Mora, Jaume, Cavieres, Isabel, Chandramohan, Arthika, Chantada, Guillermo L, Chaudhry, Shabana, Chawla, Bhavna, Chen, Wensi, Chiwanga, Faraja S, Chuluunbat, Tsengelmaa, Cieslik, Krzysztof, Clark, Antony, Cockcroft, Ruellyn L, Comsa, Codruta, Correa Llano, Maria G, Corson, Timothy W, Couitchere, Line, Cowan-Lyn, Kristin E, Csóka, Monika, Dangboon, Wantanee, Das, Anirban, Das, Pranab, Das, Sima, Davanzo, Jacquelyn M, Davidson, Alan, De Francesco, Sonia, De Potter, Patrick, Quintero D, Karina, Demirci, Hakan, Desjardins, Laurence, Díaz Coronado, Rosdali Y, Dimaras, Helen, Dodgshun, Andrew J, Donato Macedo, Carla R, Dragomir, Monica D, Du, Yi, Du Bruyn, Magritha, Du Plessis, Johannes, Dudeja, Gagan, Eerme, Katrin, Eka Sutyawan, I Wayan, El Kettani, Asmaa, Elbahi, Amal M, Elder, James E, Elhaddad, Alaa M, Elhassan, Moawia MA, Elzembely, Mahmoud M, Ericksen, Connor, Essuman, Vera A, Evina, Ted Grimbert A, Ezegwui, Ifeoma R, Fadoo, Zehra, Fandiño, Adriana C, Faranoush, Mohammad, Fasina, Oluyemi, Fernández, Delia DPG, Fernández-Teijeiro, Ana, Foster, Allen, Frenkel, Shahar, Fu, Ligia D, Fuentes-Alabi, Soad L, Garcia, Juan L, García Aldana, David, Garcia Pacheco, Henry N, Geel, Jennifer A, Ghassemi, Fariba, Girón, Ana V, Goenz, Marco A, Gold, Aaron S, Goldberg, Hila, Gole, Glen A, Gomel, Nir, Gonzalez, Efren, Gonzalez Perez, Graciela, González-Rodríguez, Liudmira, Gorfine, Malka, Graells, Jaime, Gregersen, Pernille A, Grigorovski, Nathalia DAK, Guedenon, Koffi M, Gunasekera, D Sanjeeva, Gündüz, Ahmet K, Gupta, Himika, Gupta, Sanjiv, Gupta, Vineeta, Hadjistilianou, Theodora, Hamel, Patrick, Hamid, Syed A, Hamzah, Norhafizah, Hansen, Eric D, Harbour, J William, Hartnett, M. Elizabeth, Hasanreisoglu, Murat, Muhammad, Hassan, Hassan, Sadiq, Hassan, Shadab, Hautz, Wojciech, Haydar, Huda, Hederova, Stanislava, Hessissen, Laila, Hongeng, Suradej, Hordofa, Diriba F, Hubbard, G. Baker, Hummelen, Marlies, Husakova, Kristina, Hussein Al-Janabi, Allawi N, Ibanga, Affiong, Ida, Russo, Ilic, Vesna R, Islamov, Ziyavuddin, Jairaj, Vivekaraj, Janjua, Teyyeb, Jeeva, Irfan, Ji, Xunda, Jo, Dong Hyun, Jones, Michael M, Kabesha Amani, Theophile B, Kabore, Rolande L, Kaliki, Swathi, Kalinaki, Abubakar, Kamsang, Pius, Kantar, Mehmet, Kapelushnik, Noa, Kardava, Tamar, Kebudi, Rejin, Keomisy, Jonny, Kepak, Tomas, Ketteler, Petra, Khan, Zohora J, Khaqan, Hussain A, Khetan, Vikas, Khodabande, Alireza, Khotenashvili, Zaza, Kim, Jonathan W, Kim, Jeong Hun, Kiratli, Hayyam, Kivela, Tero T., Klett, Artur, Koç, Irem, Kosh Komba Palet, Jess Elio, Krivaitiene, Dalia, Kruger, Mariana, Kulvichit, Kittisak, Kuntorini, Mayasari W, Kyara, Alice, Lam, Geoffrey C, Larson, Scott A, Latinović, Slobodanka, Laurenti, Kelly D, Lavy, Yotam, Lavric Groznik, Alenka, Leverant, Amy A, Li, Cairui, Li, Kaijun, Limbu, Ben, Liu, Chun-Hsiu, Quah, BoonLong, López, Juan P, Lukamba, Robert M, Luna-Fineman, Sandra, Lutfi, Delfitri, Lysytsia, Lesia, Madgar, Shiran, Magrath, George N, Mahajan, Amita, Maitra, Puja, Maka, Erika, Makimbetov, Emil K, Maktabi, Azza, Maldonado, Carlos, Mallipatna, Ashwin, Manudhane, Rebecca, Manzhuova, Lyazat, Martín-Begue, Nieves, Masud, Sidra, Matende, Ibrahim O, Mattosinho, Clarissa CDS, Matua, Marchelo, Mayet, Ismail, Mbumba, Freddy B, McKenzie, John D, Mehrvar, Azim, Mengesha, Aemero A, Menon, Vikas, Mercado, Gary John V, Mets, Marilyn B, Midena, Edoardo, Miller, Audra, Mishra, Divyansh KC, Mndeme, Furahini G, Mohamedani, Ahmed A, Mohammad, Mona T, Moll, Annette C, Montero, Margarita M, Moreira, Claude, Mruthyunjaya, Prithvi, Msina, Mchikirwa S, Msukwa, Gerald, Mudaliar, Sangeeta S, Muma, Kangwa I M, Munier, Francis L, Murray, Timothy G, Musa, Kareem O, Mushtaq, Asma, Musika, Anne A, Mustak, Hamzah, Mustapha, Tajudeen, Muyen, Okwen M, Myezo, Khumo H, Naidu, Gita, Naidu, Natasha, Nair, Akshay Gopinathan, Natarajan, Sundaram, Naumenko, Larisa, Ndoye Roth, Paule Aïda, Nency, Yetty M, Neroev, Vladimir, Ng, Yvonne, Nikitovic, Marina, Nkanga, Elizabeth D, Nkumbe, Henry E, Numbi, Marcel N, Nummi, Kalle, Nuruddin, Murtuza, Nyaywa, Mutale, Nyirenda, Chinsisi, Obono-Obiang, Ghislaine, Oliver, Scott CN, Oporto, Joaquin, Ortega-Hernández, Miriam, Oscar, Alexander H, Ossandon, Diego, Pagarra, Halimah, Paintsil, Vivian, Paiva, Luisa, Palanivelu, Mahesh Shanmugam, Papyan, Ruzanna, Parrozzani, Raffaele, Pascual Morales, Claudia R, Paton, Katherine E, Pe'er, Jacob, Peralta Calvo, Jesús, Perić, Sanja, Pham, Chau TM, Philbert, Remezo, Plager, David A, Pochop, Pavel, Polania, Rodrigo A., Polyakov, Vladimir, Ponce, Jimena, Qadir, Ali O, Qayyum, Seema, Qian, Jiang, Refaeli, David, Rahman, Ardizal, Rajkarnikar, Purnima, Ramanjulu, Rajesh, Ramasubramanian, Aparna, Ramirez-Ortiz, Marco A, Randhawa, Jasmeen K, Randrianarisoa, Hoby Lalaina, Raobela, Léa, Rashid, Riffat, Reddy, M.A., Renner, Lorna A, Reynders, David, Ribadu, Dahiru, Ritter-Sovinz, Petra, Rogowska, Anna, Rojanaporn, Duangnate, Romero, Livia, Roy, Soma R, Saab, Raya H, Saakyan, Svetlana, Sabhan, Ahmed H, Sagoo, Mandeep S, Said, Azza MA, Saiju, Rohit, Salas, Beatriz, San Román Pacheco, Sonsoles, Sánchez, Gissela L, Sanchez Orozco, Alma Janeth, Sayalith, Phayvanh, Scanlan, Trish A, Schlüter, Sabrina, Schwab, Christoph, Sedaghat, Ahad, Seth, Rachna, Sgroi, Mariana, Shah, Ankoor S, Shakoor, Shawkat A, Sharma, Manoj K, Sherief, Sadik T, Shields, Carol L, Sia, David, Siddiqui, Sorath Noorani, Sidi cheikh, Sidi, Silva, Sónia, Singh, Arun D, Singh, Usha, Singha, Penny, Sitorus, Rita S, Skalet, Alison H, Soebagjo, Hendrian D, Sorochynska, Tetyana, Ssali, Grace, Stacey, Andrew W, Staffieri, Sandra E, Stahl, Erin D, Steinberg, David M, Stones, David K, Strahlendorf, Caron, Suarez, Maria Estela Coleoni, Sultana, Sadia, Sun, Xiantao, Superstein, Rosanne, Supriyadi, Eddy, Surukrattanaskul, Supawan, Suzuki, Shigenobu, Svojgr, Karel, Sylla, Fatoumata, Tamamyan, Gevorg, Tan, Deborah, Tandili, Alketa, Tang, Jing, Tarrillo Leiva, Fanny F, Tashvighi, Maryam, Tateshi, Bekim, Teh, Kok Hoi, Tehuteru, Edi S, Teixeira, Luiz F, Tekavcic Pompe, Manca, Thawaba, Abdullah Dahan M, Theophile, Tuyisabe, Toledano, Helen, Trang, Doan L, Traoré, Fousseyni, Tripathy, Devjyoti, Tuncer, Samuray, Tyau-Tyau, Harba, Umar, Ali B, Unal, Emel, Uner, Ogul E, Urbak, Steen F, Ushakova, Tatiana L, Usmanov, Rustam H, Valeina, Sandra, Valente, Paola, van Hoefen Wijsard, Milo, Vasquez Anchaya, Jacqueline Karina, Vaughan, Leon O, Veleva-Krasteva, Nevyana V, Verma, Nishant, Victor, Andi A, Viksnins, Maris, Villacís Chafla, Edwin G, Villegas, Victor M, Vishnevskia-Dai, Victoria, Waddell, Keith, Wali, Amina H, Wang, Yi-Zhuo, Wangtiraumnuay, Nutsuchar, Wetter, Julie, Widiarti, Widiarti, Wilson, Matthew W, Wime, Amelia DC, Wiwatwongwana, Atchareeya, Wiwatwongwana, Damrong, Wolley Dod, Charlotte, Wong, Emily S, Wongwai, Phanthipha, Wu, Si-qi, Xiang, Daoman, Xiao, Yishuang, Xu, Bing, Xue, Kang, Yaghy, Antonio, Yam, Jason C, Yang, Huasheng, Yanga, Jenny M, Yaqub, Muhammad A, Yarovaya, Vera A, Yarovoy, Andrey A, Ye, Huijing, Yee, Roberto I, Yousef, Yacoub A, Yuliawati, Putu, Zapata López, Arturo M, Zein, Ekhtelbenina, Zhang, Yi, Zhilyaeva, Katsiaryna, Zia, Nida, Ziko, Othman AO, Zondervan, Marcia, and Bowman, Richard

Published
2022
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18. Superconductivity at 33 - 37 K in $ALn_2$Fe$_4$As$_4$O$_2$ ($A$ = K and Cs; $Ln$ = Lanthanides)

Author

Wu, Si-Qi, Wang, Zhi-Cheng, He, Chao-Yang, Tang, Zhang-Tu, Liu, Yi, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science
Abstract

We have synthesized 10 new iron oxyarsenides, K$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Gd, Tb, Dy, and Ho) and Cs$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Nd, Sm, Gd, Tb, Dy, and Ho), with the aid of lattice-match [between $A$Fe$_2$As$_2$ ($A$ = K and Cs) and $Ln$FeAsO] approach. The resultant compounds possess hole-doped conducting double FeAs layers, [$A$Fe$_4$As$_4$]$^{2-}$, that are separated by the insulating [$Ln_2$O$_2$]$^{2+}$ slabs. Measurements of electrical resistivity and dc magnetic susceptibility demonstrate bulk superconductivity at $T_\mathrm{c}$ = 33 - 37 K. We find that $T_\mathrm{c}$ correlates with the axis ratio $c/a$ for all 12442-type superconductors discovered. Also, $T_\mathrm{c}$ tends to increase with the lattice mismatch, implying a role of lattice instability for the enhancement of superconductivity., Comment: 8 pages, 6 figures, 2 tables

Published
2017
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19. Synthesis, crystal structure and superconductivity in Rb$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Sm, Tb, Dy and Ho)

Author

Wang, Zhi-Cheng, He, Chao-Yang, Wu, Si-Qi, Tang, Zhang-Tu, Liu, Yi, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science
Abstract

We have synthesized four iron-based oxyarsenide superconductors Rb$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Sm, Tb, Dy and Ho) resulting from the intergrowth of RbFe$_2$As$_2$ and $Ln$FeAsO. It is found that the lattice match between RbFe$_2$As$_2$ and $Ln$FeAsO is crucial for the phase formation. The structural intergrowth leads to double asymmetric Fe$_2$As$_2$ layers that are separated by insulating $Ln_2$O$_2$ slabs. Consequently, the materials are intrinsically doped at a level of 0.25 holes/Fe-atom and, bulk superconductivity emerges at $T_\mathrm{c}$ = 35.8, 34.7, 34.3 and 33.8 K, respectively, for $Ln$ = Sm, Tb, Dy and Ho. Investigation on the correlation between crystal structure and $T_\mathrm{c}$ suggests that interlayer couplings may play an additional role for optimization of superconductivity., Comment: 20 pages, 9 figures, 1 table

Published
2017
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20. Crystal Structure and Superconductivity at about 30 K in $A$Ca$_2$Fe$_4$As$_4$F$_2$ ($A$ = Rb, Cs)

Author

Wang, Zhi-Cheng, He, Chao-Yang, Tang, Zhang-Tu, Wu, Si-Qi, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity
Abstract

We have synthesized two iron fluo-arsenides $A$Ca$_2$Fe$_4$As$_4$F$_2$ with $A$ = Rb and Cs, analogous to the newly discovered superconductor KCa$_2$Fe$_4$As$_4$F$_2$. The quinary inorganic compounds crystallize in a body-centered tetragonal lattice with space group I4/mmm, which contain double Fe$_2$As$_2$ layers that are separated by insulating Ca$_2$F$_2$ layers. Our electrical and magnetic measurements on the polycrystalline samples demonstrate that the new materials undergo superconducting transitions at Tc = 30.5 K and 28.2 K, respectively, without extrinsic doping. The correlations between Tc and structural parameters are discussed., Comment: 9 pages,4 figures, 1 table

Published
2017
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21. Superconductivity in KCa$_2$Fe$_4$As$_4$F$_2$ with Separate Double Fe$_2$As$_2$ Layers

Author

Wang, Zhi-Cheng, He, Chao-Yang, Wu, Si-Qi, Tang, Zhang-Tu, Liu, Yi, Ablimit, Abduweli, Feng, Chun-Mu, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

We report synthesis, crystal structure and physical properties of a quinary iron-arsenide fluoride KCa$_2$Fe$_4$As$_4$F$_2$. The new compound crystallizes in a body-centered tetragonal lattice (with space group $I4/mmm$, $a$ = 3.8684(2) {\AA}, c = 31.007(1) {\AA}, and $Z$ = 2), which contains double Fe$_2$As$_2$ conducting layers separated by insulating Ca$_2$F$_2$ layers. Our measurements of electrical resistivity, dc magnetic susceptibility and heat capacity demonstrate bulk superconductivity at 33 K in KCa$_2$Fe$_4$As$_4$F$_2$., Comment: 11 pages, 7 figures, 2 tables

Published
2016
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22. Superconductivity at 35 K by self doping in RbGd$_2$Fe$_4$As$_4$O$_2$

Author

Wang, Zhi-Cheng, He, Chao-Yang, Wu, Si-Qi, Tang, Zhang-Tu, Liu, Yi, Ablimit, Abduweli, Tao, Qian, Feng, Chun-Mu, Xu, Zhu-An, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity
Abstract

We report synthesis, crystal structure and physical properties of a novel quinary compound RbGd$_2$Fe$_4$As$_4$O$_2$. The new iron oxyarsenide is isostructural to the fluo-arsenide KCa$_2$Fe$_4$As$_4$F$_2$, both of which contain separate double Fe$_2$As$_2$ layers that are self hole-doped in the stoichiometric composition. Bulk superconductivity at $T_\mathrm{c}$ = 35 K is demonstrated by the measurements of electrical resistivity, dc magnetic susceptibility and heat capacity. An exceptionally high value of the initial slope of the upper critical field ($\mu_0$d$H_{\mathrm{c2}}$/d$T|_{T_\mathrm{c}}$ = 16.5 T/K) is measured for the polycrystalline sample., Comment: 10 pages, 6 figures, 1 table, the crystal structure is amended

Published
2016
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24. Anomalous Eu Valence State and Superconductivity in Undoped Eu3Bi2S4F4

Author

Zhai, Hui-Fei, Zhang, Pan, Wu, Si-Qi, He, Chao-Yang, Tang, Zhang-Tu, Jiang, Hao, Sun, Yun-Lei, Bao, Jin-Ke, Nowik, I., Felner, I., Zeng, Yue-Wu, Li, Yu-Ke, Xu, Xiao-Feng, Tao, Qian, Xu, Zhu-An, and Cao, Guang-Han

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

We have synthesized a novel europium bismuth sulfofluoride, Eu3Bi2S4F4, by solid-state reactions in sealed evacuated quartz ampoules. The compound crystallizes in a tetragonal lattice (space group I4/mmm, a = 4.0771(1) A, c = 32.4330(6) A, and Z = 2), in which CaF2-type Eu3F4 layers and NaCl-like BiS2 bilayers stack alternately along the crystallographic c axis. There are two crystallographically distinct Eu sites, Eu(1) and Eu(2) at the Wyckoff positions 4e and 2a, respectively. Our bond-valence-sum calculation, based on the refined structural data, indicates that Eu(1) is essentially divalent, whilst Eu(2) has an average valence of +2.64(5). This anomalous Eu valence state is further confirmed and supported, respectively, by Mossbauer and magnetization measurements. The Eu3+ components donate electrons into the conduction bands that are mainly composed of Bi- 6px and 6py states. Consequently, the material itself shows metallic conduction, and superconducts at 1.5 K without extrinsic chemical doping., Comment: 24 pages, 5 figures

Published
2014
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25. Research progress on randomization methods in clinical trials.

Author

WU Si-qi, WANG Xiao-jin, and WANG Bing-shun

Subjects
*CLINICAL trials, *RESEARCH personnel, *BLOCK designs, *INTEGRITY, *MEDICAL misconceptions
Abstract

Objective To summarize the performance and implementation status of various randomization methods, and to provide clinical researchers with a guide for choosing an appropriate randomization method and executing it in a standardized manner. Methods The review elucidated the conceptual and implementation integrity of randomization, and illuminated the developmental history and application of major randomization methods, as well as their performance in the two competitive dimensions of group allocation randomness and group sample balance. Results Restricted randomization was frequently used to maintain an appropriate treatment balance in practice. Block randomization was the most widely used, but its allocation sequence lacked sufficient randomness and could be predicted, elevating the risk of selection bias, especially in open-label trials. Methods offering a superior trade-off between randomness and balance included MTI restricted randomization methods like the big stick design and maximal procedure, as well as combinations of multiple randomization methods such as the block urn design and sandwich mixed randomization. Many clinical researchers still had misconceptions about the randomization concept itself and often overlooked its critical methodological rigor and standardized implementation. Conclusion Researchers should meticulously choose a suitable randomization method and report implementation details in a standardized manner, allowing peer researchers to evaluate the internal validity and evidence strength of the study. Due to its high predictability, the widely used block randomization method should be substituted by alternative methods with better performance. Future randomization procedures can be explored and developed based on the MTI restrictive methods and the combinations of existing methods. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Delayed improvements in visual memory task performance among chronic schizophrenia patients after high-frequency repetitive transcranial magnetic stimulation

Author

Du, Xiang-Dong, primary, Li, Zhe, additional, Yuan, Nian, additional, Yin, Ming, additional, Zhao, Xue-Li, additional, Lv, Xiao-Li, additional, Zou, Si-Yun, additional, Zhang, Jun, additional, Zhang, Guang-Ya, additional, Li, Chuan-Wei, additional, Pan, Hui, additional, Yang, Li, additional, Wu, Si-Qi, additional, Yue, Yan, additional, Wu, Yu-Xuan, additional, and Zhang, Xiang-Yang, additional

Published
2022
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29. Baseline serum uric acid level is associated with progression-free survival, disease control rate, and safety in postoperative patients with colorectal cancer treated by FOLFOX, FOLFIRI, or XELOX

Author

Zhang, Xi, primary, Chen, Qing-hong, additional, Yang, Ying, additional, Lin, Jing-xin, additional, Li, Yan-chun, additional, Zhong, Tian-yu, additional, Chen, Jie, additional, Wu, Si-qi, additional, Chen, Xiao-hu, additional, Zhou, Rui-si, additional, Lin, Jia-man, additional, Wang, Dong-qing, additional, He, Qiu-xing, additional, You, Yan-ting, additional, Zhou, Xing-hong, additional, Zuo, Qiang, additional, Liu, Yan-yan, additional, Cheng, Jing-ru, additional, Wu, Yi-fen, additional, and Zhao, Xiao-shan, additional

Published
2022
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