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2,522 results on '"Kim, Mi Kyung"'

1. Strain tunable electronic ground states in two-dimensional iridate thin films

Author

Kim, Donghan, Sohn, Byungmin, Lee, Yeonjae, Song, Jeongkeun, Kim, Mi Kyung, Kim, Minjae, Noh, Tae Won, and Kim, Changyoung

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

Quantum phases of matter such as superconducting, ferromagnetic and Wigner crystal states are often driven by the two-dimensionality (2D) of correlated systems. Meanwhile, spin-orbit coupling (SOC) is a fundamental element leading to nontrivial topology which gives rise to quantum phenomena such as the large anomalous Hall effect and nontrivial superconductivity. However, the search for controllable platforms with both 2D and SOC has been relatively overlooked so far. Here, we control and study the electronic ground states of iridate ultrathin films having both 2D and SOC by angle-resolved photoemission spectroscopy (ARPES) and dynamical mean field theory (DMFT) calculations. The metallicity of SrIrO$_3$ ultrathin films is controlled down to a monolayer by dimensional and strain manipulation. Our results suggest that the iridate ultrathin films can be a controllable 2D SOC platform exhibiting a variety of phenomena for future functional devices., Comment: 7 pages, 4 figures

Published
2024
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6. Collective magnetic Higgs excitation in a pyrochlore ruthenate

Author

Wulferding, Dirk, Kim, Junkyeong, Kim, Mi Kyung, Yang, Yang, Lee, Jae Hyuck, Song, Dongjoon, Oh, Dongjin, Kim, Heung-Sik, Chern, Li Ern, Kim, Yong Baek, Noh, Minji, Choi, Hyunyong, Choi, Sungkyun, Perkins, Natalia B., Kim, Changyoung, and Park, Seung Ryong

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

The emergence of scalar Higgs-type amplitude modes in systems where symmetry is spontaneously broken has been a highly successful, paradigmatic description of phase transitions, with implications ranging from high-energy particle physics to low-energy condensed matter systems. Here, we uncover two successive high temperature phase transitions in the pyrochlore magnet Nd$_2$Ru$_2$O$_7$ at $T_{\mathrm{N}} = 147$ K and $T^* = 97$ K, that lead to giant phonon instabilities and culminate in the emergence of a highly coherent excitation. This coherent excitation, distinct from other phonons and from conventional magnetic modes, stabilizes at a low energy of 3 meV. We assign it to a collective Higgs-type amplitude mode, that involves bond energy modulations of the Ru$_4$ tetrahedra. Its striking two-fold symmetry, incompatible with the underlying crystal structure, highlights the possibility of multiple entangled broken symmetries.

Published
2022
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7. Sign-tunable anisotropic magnetoresistance and electrically detectable dual magnetic phases in a helical antiferromagnet

Author

Kim, Jong Hyuk, Shin, Hyun Jun, Kim, Mi Kyung, Hong, Jae Min, Jeong, Ki Won, Kim, Jin Seok, Moon, Kyungsun, Lee, Nara, and Choi, Young Jai

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The helimagnetic order describes a non-collinear spin texture of antiferromagnets, arising from competing exchange interactions. Although collinear antiferromagnets are elemental building blocks of antiferromagnetic (AFM) spintronics, the potential of implementing spintronic functionality in non-collinear antiferromagnets has not been clarified thus far. Here, we propose an AFM helimagnet of EuCo2As2 as a novel single-phase spintronic material that exhibits a remarkable sign reversal of anisotropic magnetoresistance (AMR). The contrast in the AMR arises from two electrically distinctive magnetic phases with spin reorientation driven by magnetic field lying on the easy-plane, which switches the sign of the AMR from positive to negative. Further, various AFM memory states associated with the evolution of the spin structure under magnetic fields were identified theoretically, based on an easy-plane anisotropic spin model. These results reveal that non-collinear antiferromagnets hold potential for developing spintronic devices.

Published
2022

8. Large anomalous Hall effect and anisotropic magnetoresistance in intrinsic nanoscale spin-valve-type structure of an antiferromagnet

Author

Oh, Dong Gun, Kim, Jong Hyuk, Kim, Mi Kyung, Shin, Ki Won Jeong Hyun Jun, Hong, Jae Min, Kim, Jin Seok, Moon, Kyungsun, Lee, Nara, and Choi, Young Jai

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

A spin valve is a prototype of spin-based electronic devices found on ferromagnets, in which an antiferromagnet plays a supporting role. Recent findings in antiferromagnetic spintronics show that an antiferromagnetic order in single-phase materials solely governs dynamic transport, and antiferromagnets are considered promising candidates for spintronic technology. In this work, we demonstrated antiferromagnet-based spintronic functionality on an itinerant Ising antiferromagnet of Ca0.9Sr0.1Co2As2 by integrating nanoscale spin-valve-type structure and investigating anisotropic magnetic properties driven by spin-flips. Multiple stacks of 1 nm thick spin-valve-like unit are intrinsically embedded in the antiferromagnetic spin structure. In the presence of a rotating magnetic field, a new type of the spin-valve-like operation was observed for large anomalous Hall conductivity and anisotropic magnetoresistance, whose effects are maximized above the spin-flip transition. In addition, a joint experimental and theoretical study provides an efficient tool to read out various spin states, which scheme can be useful for implementing extensive spintronic applications.

Published
2022

17. Spin-orbit coupling driven orbital-selective doping effect in Sr2Ru1−xIrxO4

Author

Kwon, Junyoung, Kim, Beom Seo, Kim, Mi Kyung, Denlinger, Jonathan, Bostwick, Aaron, Rotenberg, Eli, Lee, Nara, Choi, Hwan Young, Moon, Jae Young, Choi, Young Jai, Mun, Junsik, Kim, Miyoung, Yoshida, Yoshiyuki, Kyung, Wonshik, and Kim, Changyoung

Subjects
Physical Sciences, Condensed Matter Physics, Chemical sciences, Engineering, Physical sciences
Abstract

Orbital-selective phenomena in mutliorbital systems have received much attention due to their uniqueness as well as possible connections to other phenomena. As orbital-selectiveness is mostly related to the crystal structure, finding a new control parameter other than structure would be of significant importance. Here we report discovery of an orbital-selective doping effect in Sr2Ru1-xIrxO4 (SRIO). Our systematic electronic structure study of SRIO reveals an anomalous orbital-selective doping effect and concomitant Lifshitz transitions (LTs) in the γ band. With the help of a tight-binding calculation, we find that the orbital-selective doping effect is due to variation in the spin-orbit coupling (SOC) strength. Our findings not only elucidate the mechanism of LTs in the γ band in SRIO but may also open new avenues for novel SOC-controlled orbital-selective phenomena.

Published
2021

26. Gene-Environment Interactions Relevant to Estrogen and Risk of Breast Cancer: Can Gene-Environment Interactions Be Detected Only among Candidate SNPs from Genome-Wide Association Studies?

Author

Park, JooYong, Choi, Ji-Yeob, Choi, Jaesung, Chung, Seokang, Song, Nan, Park, Sue K, Han, Wonshik, Noh, Dong-Young, Ahn, Sei-Hyun, Lee, Jong Won, Kim, Mi Kyung, Jee, Sun Ha, Wen, Wanqing, Bolla, Manjeet K, Wang, Qin, Dennis, Joe, Michailidou, Kyriaki, Shah, Mitul, Conroy, Don M, Harrington, Patricia A, Mayes, Rebecca, Czene, Kamila, Hall, Per, Teras, Lauren R, Patel, Alpa V, Couch, Fergus J, Olson, Janet E, Sawyer, Elinor J, Roylance, Rebecca, Bojesen, Stig E, Flyger, Henrik, Lambrechts, Diether, Baten, Adinda, Matsuo, Keitaro, Ito, Hidemi, Guénel, Pascal, Truong, Thérèse, Keeman, Renske, Schmidt, Marjanka K, Wu, Anna H, Tseng, Chiu-Chen, Cox, Angela, Cross, Simon S, kConFab Investigators, Andrulis, Irene L, Hopper, John L, Southey, Melissa C, Wu, Pei-Ei, Shen, Chen-Yang, Fasching, Peter A, Ekici, Arif B, Muir, Kenneth, Lophatananon, Artitaya, Brenner, Hermann, Arndt, Volker, Jones, Michael E, Swerdlow, Anthony J, Hoppe, Reiner, Ko, Yon-Dschun, Hartman, Mikael, Li, Jingmei, Mannermaa, Arto, Hartikainen, Jaana M, Benitez, Javier, González-Neira, Anna, Haiman, Christopher A, Dörk, Thilo, Bogdanova, Natalia V, Teo, Soo Hwang, Mohd Taib, Nur Aishah, Fletcher, Olivia, Johnson, Nichola, Grip, Mervi, Winqvist, Robert, Blomqvist, Carl, Nevanlinna, Heli, Lindblom, Annika, Wendt, Camilla, Kristensen, Vessela N, Nbcs Collaborators, Tollenaar, Rob AEM, Heemskerk-Gerritsen, Bernadette AM, Radice, Paolo, Bonanni, Bernardo, Hamann, Ute, Manoochehri, Mehdi, Lacey, James V, Martinez, Maria Elena, Dunning, Alison M, Pharoah, Paul DP, Easton, Douglas F, Yoo, Keun-Young, and Kang, Daehee

Subjects
Biomedical and Clinical Sciences, Oncology and Carcinogenesis, Estrogen, Women's Health, Aging, Breast Cancer, Human Genome, Genetics, Prevention, Cancer, Clinical Research, 2.1 Biological and endogenous factors, Aetiology, breast cancer, estrogen, gene-environment interaction, Oncology and carcinogenesis
Abstract

In this study we aim to examine gene-environment interactions (GxEs) between genes involved with estrogen metabolism and environmental factors related to estrogen exposure. GxE analyses were conducted with 1970 Korean breast cancer cases and 2052 controls in the case-control study, the Seoul Breast Cancer Study (SEBCS). A total of 11,555 SNPs from the 137 candidate genes were included in the GxE analyses with eight established environmental factors. A replication test was conducted by using an independent population from the Breast Cancer Association Consortium (BCAC), with 62,485 Europeans and 9047 Asians. The GxE tests were performed by using two-step methods in GxEScan software. Two interactions were found in the SEBCS. The first interaction was shown between rs13035764 of NCOA1 and age at menarche in the GE|2df model (p-2df = 1.2 × 10-3). The age at menarche before 14 years old was associated with the high risk of breast cancer, and the risk was higher when subjects had homozygous minor allele G. The second GxE was shown between rs851998 near ESR1 and height in the GE|2df model (p-2df = 1.1 × 10-4). Height taller than 160 cm was associated with a high risk of breast cancer, and the risk increased when the minor allele was added. The findings were not replicated in the BCAC. These results would suggest specificity in Koreans for breast cancer risk.

Published
2021

27. Associations between exploratory dietary patterns and incident type 2 diabetes: a federated meta-analysis of individual participant data from 25 cohort studies

Author

Jannasch, Franziska, Dietrich, Stefan, Bishop, Tom R. P., Pearce, Matthew, Fanidi, Anouar, O’Donoghue, Gráinne, O’Gorman, Donal, Marques-Vidal, Pedro, Vollenweider, Peter, Bes-Rastrollo, Maira, Byberg, Liisa, Wolk, Alicja, Hashemian, Maryam, Malekzadeh, Reza, Poustchi, Hossein, Luft, Vivian C., de Matos, Sheila M. Alvim, Kim, Jihye, Kim, Mi Kyung, Kim, Yeonjung, Stern, Dalia, Lajous, Martin, Magliano, Dianna J., Shaw, Jonathan E., Akbaraly, Tasnime, Kivimaki, Mika, Maskarinec, Gertraud, Le Marchand, Loïc, Martínez-González, Miguel Ángel, Soedamah-Muthu, Sabita S., Wareham, Nicholas J., Forouhi, Nita G., and Schulze, Matthias B.

Published
2022
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28. Efficacy and safety of enavogliflozin versus dapagliflozin added to metformin plus gemigliptin treatment in patients with type 2 diabetes: a double-blind, randomized, comparator-active study: ENHANCE-D study

Author

Kim, Kyung-Soo, Han, Kyung Ah, Kim, Tae Nyun, Park, Cheol-Young, Park, Jung Hwan, Kim, Sang Yong, Kim, Yong Hyun, Song, Kee Ho, Kang, Eun Seok, Kim, Chul Sik, Koh, Gwanpyo, Kang, Jun Goo, Kim, Mi Kyung, Han, Ji Min, Kim, Nan Hee, Mok, Ji Oh, Lee, Jae Hyuk, Lim, Soo, Kim, Sang Soo, Kim, Tae Ho, Won, Kyu Chang, Lee, Ki Young, Cho, Jae Hyoung, Han, Ju Young, Kim, So Hun, Nah, Jae Jin, Song, Hwa Rang, Lee, Si Eun, and Kim, Sungrae

Published
2023
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31. A multicentre, double‐blind, placebo‐controlled, randomized, parallel comparison, phase 3 trial to evaluate the efficacy and safety of pioglitazone add‐on therapy in type 2 diabetic patients treated with metformin and dapagliflozin

Author

Lim, Soo, primary, Lee, Seung‐Hwan, additional, Min, Kyung‐Wan, additional, Lee, Chang Beom, additional, Kim, Sang Yong, additional, Yoo, Hye Jin, additional, Kim, Nan Hee, additional, Kim, Jae Hyeon, additional, Oh, Seungjoon, additional, Won, Jong Chul, additional, Kwon, Hyuk Sang, additional, Kim, Mi Kyung, additional, Park, Jung Hwan, additional, Jeong, In‐Kyung, additional, and Kim, Sungrae, additional

Published
2024
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41. Tunable Colossal Anomalous Hall Conductivity in Half‐Metallic Material Induced by d‐Wave‐Like Spin‐Orbit Gap.

Author

Choi, Joonyoung, Park, Jin‐Hong, Kyung, Wonshik, Kim, Younsik, Kim, Mi Kyung, Kwon, Junyoung, Kim, Changyoung, Rhim, Jun‐Won, Park, Se Young, and Jo, Younjung

Subjects
MAGNETIC sensors, MAGNETIC materials, DENSITY functional theory, ANOMALOUS Hall effect, BRILLOUIN zones, SPIN-orbit interactions
Abstract

The anomalous Hall conductivity (AHC) in magnetic materials, resulting from inverted band topology, has emerged as a key adjustable function in spin‐torque devices and advanced magnetic sensors. Among systems with near‐half‐metallicity and broken time‐reversal symmetry, cobalt disulfide (CoS2) has proven to be a material capable of significantly enhancing its AHC. In this study, the AHC of CoS2 is empirically assessed by manipulating the chemical potential through Fe‐ (hole) and Ni‐ (electron) doping. The primary mechanism underlying the colossal AHC is identified through the application of density functional theory and tight‐binding analyses. The main source of this substantial AHC is traced to four spin‐polarized massive Dirac dispersions in the kz = 0 plane of the Brillouin zone, located slightly below the Fermi level. In Co0.95Fe0.05S2, the AHC, which is directly proportional to the momentum‐space integral of the Berry curvature (BC), reached a record‐breaking value of 2507 Ω−1cm−1. This is because the BCs of the four Dirac dispersions all exhibit the same sign, a consequence of the d‐wave‐like spin‐orbit coupling among spin‐polarized eg orbitals. [ABSTRACT FROM AUTHOR]

Published
2024
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