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Exposures of enclave-bearing granitoids can provide rare opportunities to directly evaluate the connection between compositional variability and the depth of origin of arc magmatic rocks. The ∼1000 km long Gangdese batholith is a composite batholith with composition from mafic to felsic; SiO2 ranges from 51 wt% to 70 wt%. New zircon U−Pb dating of the Nyemo plutons, Renbu plutons, and Xigaze plutons in the Gangdese batholith is consistent with their emplacement and crystallization in the Late Cretaceous (ca. 90−85 Ma). Mafic magmatic enclaves (MMEs) in the plutons are characterized by low SiO2 (50.9−56.0 wt%) and Nb/U, Ce/Pb, and Nb/La ratios coupled with enrichment in light rare earth elements and large ion lithophile elements and depletion in high field strength elements. These geochemical features, combined with depleted whole-rock εNd(t) (+4.2 to +4.7) and zircon εHf(t) (+9.0 to +13.8), suggest that they were derived by partial melting of a depleted mantle source associated with subduction-related fluids. The granitoids with high SiO2 (55.6−66.9 wt%) display adakitic geochemical characteristics, such as low Y and Yb contents, and high Sr/Y and La/Yb ratios. Their positive whole-rock εNd(t) (+4.0 to +5.5) and zircon εHf(t) (+6.9 to +14.3) values, as well as enrichment of incompatible elements, indicate that the granitoids were derived from partial melting of the juvenile lower crust. Geochemical modeling suggests that the compositional diversities of MMEs and adakitic granitoids were inherited from heterogeneous sources. This genetic relationship indicates that the underplated basaltic magmas could have supplied sufficient heat to trigger the melting of the thickened crust and thus formation of the enclave-bearing granitoid. In this regard, the origin of arc rocks can mirror the evolution of crustal thickness. Our results reveal that the crust was thickened to ∼50 km during the Late Cretaceous (90−85 Ma) and provide a magmatic record of crustal thickening prior to the Cenozoic Indo-Asia collision.

Quantum key distribution (QKD) allows two remote parties to share information-theoretically secure keys. In recent years, a revolutionary breakthrough called twin-field (TF) QKD has been developed to overcome the linear key-rate constraint and greatly increases the achievable distance. Phase-randomization and subsequent postselection play important roles in its security proof. Later, no-phase-postselection TF-QKD was proposed and became a popular variant, since the removal of phase postselection leads to a higher key rate. However, the achievable distance is decreased compared to the original one. Here, we propose a TF-QKD protocol with partial phase postselection. Namely, its code mode is still free from global phase randomization and postselection to make sure the advantage of the high key rate remains. On other hand, phase postselection is introduced in the decoy mode to improve the performance. Applying an operator dominance condition, we prove universal security of the proposed protocol in the finite-key case under coherent attacks, and numerical simulations confirm its potential advantages in terms of key rate and achievable distance.

We explored the effects of C:N ratio in root exudates of为探究根系分泌物C∶N对土壤养分循环及微生物活性的影响,本研究以黄土高原人工刺槐林为对象,在生境条件基本一致的15、25、35、45 a刺槐林地取原位土壤,通过模拟不同C∶N的根系分泌物(只添加N、C∶N=10、C∶N=50、C∶N=100和只添加C)添加至土壤,以去离子水作为对照,分析根系分泌物C∶N对土壤碳、氮、磷、pH值等理化特征和土壤呼吸的影响。结果表明: 1)有机碳含量与根系分泌物C∶N呈正相关,根系分泌物C∶N=10时土壤有机碳(SOC)分解较快,高根系分泌物C∶N(C∶N=100)能延缓SOC分解,而只添加C处理对SOC无显著影响。2)不同C∶N根系分泌物处理对全氮的影响不明显,碳添加能促进微生物对铵态氮的吸收,氮添加能促进铵态氮的硝化,随着根系分泌物C∶N增加,土壤中铵态氮含量下降。3)氮添加会导致土壤pH值下降,增加土壤全磷含量。4)刺槐林地土壤呼吸值与根系分泌物C∶N呈正相关,随着C∶N增加,根系分泌物对25和35 a人工刺槐林土壤呼吸的促进作用更显著。综上,根系分泌物C∶N值越高,对人工刺槐林土壤呼吸的促进作用越显著。研究结果进一步加深了对森林根系-土壤-微生物互作过程的认识。.

Quantum key distribution(QKD) allows two remote parties to share information-theoretic secret keys. Many QKD protocols assume the phase of encoding state can be continuous randomized from 0 to 2 pi, which, however, may be questionable in experiment. This is particularly the case in the recently proposed twin-field(TF) QKD, which has received a lot of attention, since it can increase key rate significantly and even beat some theoretical rate-loss limits. As an intuitive solution, one may introduce discrete phase-randomization instead of continuous one. However, a security proof for a QKD protocol with discrete phase-randomization in finite-key region is still missing. Here we develop a technique based on conjugate measurement and quantum state distinguishment to ana-lyze the security in this case. Our result shows that TF-QKD with reasonable number of discrete random phases, e.g. 8 phases from {0, pi/4, pi/2, ..., 7pi/4}, can achieve satisfactory performance. More importantly, as a the first proof for TF-QKD with discrete phase-randomization in finite-key region, our method is also applicable in other QKD protocols., 1 figures,20 pages

Monolayer WTe

As condensed-matter manifestations of the chiral anomaly, the coexistence of positive longitudinal magnetoconductivity (LMC) and the planar Hall effect (PHE) is regarded as a characteristic transport signal for the Weyl semimetal (WSM) phase. By including a finite Newtonian mass into the general linearized WSM model, we derive an analytical expression for the chiral chemical potential, which includes a topological term of the chiral anomaly and a nontopological term. The nontopological term stems from the Zeeman-field-induced tilt of the Weyl cones, which breaks the symmetry of the fermion filling between the Weyl valleys of opposite chiralities and further leads to a chiral chemical potential $\ensuremath{\propto}\mathbit{E}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbit{B}$, much as the effect of the chiral anomaly. We demonstrate that the resulting LMC is positive and can coexist with the PHE without invoking the mechanism of the chiral anomaly. Hence, the chiral chemical potential might not be exclusively respected to the chiral anomaly. Experimentally, one can distinguish the chiral anomaly from the proposed tilt mechanism by inspecting the dependence of magnetoconductivity on the Fermi energy.

Topological edge states exhibit dissipationless transport and electrically-driven topological phase transitions, making them ideal for next-generation transistors that are not constrained by Moore's law. Nevertheless, their dispersion has never been probed and is often assumed to be simply linear, without any rigorous justification. Here we determine the non-linear electrical response of topological edge states in the ballistic regime and demonstrate the way this response ascertains the presence of symmetry breaking terms in the edge dispersion, such as deviations from non-linearity and tilted spin quantization axes. The non-linear response stems from discontinuities in the band occupation on either side of a Zeeman gap, and its direction is set by the spin orientation with respect to the Zeeman field. We determine the edge dispersion for several classes of topological materials and discuss experimental measurement., 8 pages, 4 figures

The current response for the parameter change of a mesoscopic system is a practical issue for future's circuit design. Nowadays most considered cases are various types of bias modulation, while the effect of change of conductor Hamiltonian is seldom addressed. In this paper, we investigate the response of ballistic transport induced by a sudden change of the conductor Hamiltonian. We formulize the terminal current in language of non-equilibrium Green's function. Our method is applied to one-dimensional tight-binding chains and we find that the terminal current has a delay to the Hamiltonian change. The amount of delay is not determined by the velocity of incident electrons in the bias window, but depends on the tight-binding hopping energy γ. The delay of current response at the detecting point away from where the Hamiltonian changes is C γ − 1 , where C is a constant independent of the system.

Intrusive complexes with compositional diversity commonly document magma mixing processes and provide insights into regional magmatism and tectonics. Here, we present an integrated study involving detailed field investigations, petrography, mineral chemistry, whole-rock geochemistry, Sr Nd isotopic compositions, and zircon U–Pb–Hf isotopes for the Quxu intrusive complex in southern Tibet, with the aim of constraining the origin of the complex and gaining insights into the early Eocene magmatism and geodynamics of the southern Lhasa subterrane. The Quxu intrusive complex consists predominantly of tonalites and minor pyroxene–hornblende gabbronorites, with lesser amounts of quartz diorites within the contact zones of these two types of rock. Zircon LA–ICP–MS U Pb dating yields crystallization ages of ~51 Ma for all lithologies in this complex. The pyroxene–hornblende gabbronorites show replacement of pyroxene by amphibole and/or biotite and contain plagioclase crystals of variable composition (An38–74) and quartz, characteristics that are consistent with a reactive process via magma mixing. The quartz diorites and tonalites preserve plagioclase crystals with complex oscillatory zoning and repeated resorption surfaces, indicating a magma mixing origin. Geochemically, the pyroxene–hornblende gabbronorites, quartz diorites, and tonalites exhibit continuous variations in most of their major- and trace-element compositions, consistent with published data for mafic microgranular enclaves (MMEs) and host granitoids that resulted from magma mixing. All the lithologies in the Quxu intrusive complex have homogeneous and depleted isotopic compositions, with whole-rock initial 87Sr/86Sr ratios (ISr) of 0.7038–0.7041, eNd(t) values of +5.5 to +6.3, and zircon eHf(t) values of +8.5 to +12.9. These geochemical and isotopic data, combined with the mineralogical features, indicate that the Quxu intrusive complex originated from magma mixing between mafic and felsic end-members in varying proportions. The mafic end-member was derived from the decompression melting of upwelling asthenosphere, and the felsic end-member was derived from the partial melting of juvenile lower crust triggered by underplating of a mafic end-member. Our results also indicate that breakoff of the Neo-Tethyan oceanic slab was responsible for the generation of the Quxu intrusive complex and, more generally, for the early Eocene magmatism in the southern Lhasa subterrane.

Recently, the linear and nonlinear planar Hall effect (PHE) on the topological insulators (TIs) surface has been extensively studied in experiments. To explain this phenomenon, various microscopic mechanisms are proposed theoretically, and one has to employ different mechanisms to separately understand the linear and nonlinear PHE even for the same system. Here, we study the planar magnetic resistance effect in TI thin film and find that a peculiar anisotropic scattering and a spin valve structure with respect to the PHE can be caused by the tilt and shift of Dirac cones, respectively, which are induced by the combination of spin-momentum locking of surface states and an in-plane magnetic field. The tilt and shift effects can act as the origin of both the linear and nonlinear PHE by distorting the spin texture of surface states or forming the spin polarization. These two mechanisms interplay and dominate, respectively, in strong coupling (thin TI) and decoupling (thick TI) between bottom and top surfaces. For thick TI film, we show that both the linear and nonlinear PHEs induced by the tilt effect can recover the results observed in recent experiments. Our theory provides a perspective to understand the origin of both linear and nonlinear PHE observed in recent experiments.

Nodal-line semimetals are typically characterized by a nodal ring, a closed line of Dirac points in the Brillouin zone, whose topology is characterized by a quantized Berry phase. The nodal loop is protected by the combined inversion and time-reversal ($\mathcal{PT}$) symmetry in the absence of spin-orbit coupling, exhibiting the parity anomaly. Introduction of the $\mathcal{PT}$-break mass term can lead to the transverse Hall response at each point in the nodal ring, but the net Hall current vanishes due to the existence of inversion-symmetry points that contribute to the transverse current with opposite signs. We show that the combination of an inversion-broken tilt term and finite Fermi energy can cause the nonzero anomalous Hall effect. We explore the DC and AC anomalous Hall conductivity in tilted nodal-line semimetals using Kubo formula and focus on the contribution of the free carriers to the Hall conductivity. We find that the interband transition of free carriers dominates the nonvanishing dynamic Hall conductivity over the filled band contribution. The resulting anomalous Hall conductivity exhibits the parity anomaly for the DC case, and rich characteristic frequencies for the AC case which is closely related to the change of the geometry of the Fermi surface. These features may serve as a diagnostic tool to characterize the topological property, tilting parameter, or the radius of the nodal line.

We study the influence of the chiral anomaly of a time-reversal broken Weyl semimetal on Andreev reflection in a superconductor junction. It is found that the chiral chemical potential can lead to the switching between the retro Andreev reflection (RAR) and specular Andreev reflection (SAR), which appears in both intraband and interband electron-hole conversion, violating the common rule that the intraband conversion is the RAR while the interband one is the SAR. This switching effect is dependent on the tilt of the Weyl cones and the direction of the line connecting the two Weyl points. In addition, a perfect Andreev reflection is found at the incident angle, not perpendicular to the junction interface. We also discuss the zero-bias differential conductance which provides an observable signature of the switching effect, especially for the switching between RAR and SAR caused by band transition. These findings are useful in better understanding the Andreev reflection types and detecting the chiral anomaly.

Nodal-line semimetals (NLSMs) are typically characterized by a nodal ring, a closed line of Dirac points in the Brillouin zone, which features a torus-shaped Fermi surface, as well as a quantized Berry phase $\ensuremath{\pi}$. By investigating the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in NLSMs, a close relationship between the magnetic interaction and the radius ${k}_{0}$ of the nodal ring is revealed. For impurities deposited in the direction normal to the nodal-ring plane, when the long-range interaction at half-band filling follows the decaying law ${R}^{\ensuremath{-}3}$ with impurity distance, which is a result of anisotropic dispersion of semi-Dirac semimetal, the decaying rate for the relatively short-range impurity distance would be prolonged by nodal-ring radius ${k}_{0}$, which is prominent for the intermediate radius. This phenomenon originates from the competition between the contribution from the electron states inside and outside the nodal ring. In contrast, for impurities distributed in the nodal-ring plane, the RKKY interaction $J\ensuremath{\propto}{k}_{0}^{2}\mathrm{cos}(2{k}_{0}R){R}^{\ensuremath{-}4}$ shows an oscillation, from whose period one can easily determine the parameter ${k}_{0}$ of the nodal ring. Furthermore, at finite Fermi energy, we find a distinct signature of the RKKY interaction to characterize the topological trivial and topological nontrivial phases in NLSMs.

The authors develop a method for magnetotransport study in finite-size systems and use it to evaluate magnetoconductivity of a disordered Weyl semimetal for both the ballistic and diffusive regimes.

Recently, a novel planar Hall effect (PHE), which results from the resistivity anisotropy induced by an in-plane magnetic field, was discovered on the surface of topological insulators (TIs). While the PHE phenomenon in Weyl/Dirac semimetals is understood as a consequence of the chiral anomaly, the origin of the PHE in TIs, however, remains unclear theoretically. Several theories and experiments have ascribed the appearance of the PHE to the anisotropic backscattering induced by magnetic disorders, where the magnetization of the scatterers is indispensable. Instead, we here show that the anisotropic backscattering can arise from the tilt of the Dirac cone by an in-plane magnetic field, which emerges if nonlinear momentum terms are included, irrelevant to the magnetic nature of the scatterers. We further find that a relatively strong scalar potential can further enhance the PHE magnitude significantly, and the resulting impurity resonant state together with the tilted cone can produce the double-peak structure of the PHE and the sign change of the anisotropic magnetoresistivity. Our theory provides another perspective to understand the nontopological origin of the experimentally observed PHE in topological materials.

Quantum key distribution (QKD) can help two distant peers to share secret key bits, whose security is guaranteed by the law of physics. In practice, the secret key rate of a QKD protocol is always lowered with the increasing of channel distance, which severely limits the applications of QKD. Recently, twin-field (TF) QKD has been proposed and intensively studied, since it can beat the rate-distance limit and greatly increase the achievable distance of QKD. Remarkalebly, K. Maeda et. al. proposed a simple finite-key analysis for TF-QKD based on operator dominance condition. Although they showed that their method is sufficient to beat the rate-distance limit, their operator dominance condition is not general, i.e. it can be only applied in three decoy states scenarios, which implies that its key rate cannot be increased by introducing more decoy states, and also cannot reach the asymptotic bound even in case of preparing infinite decoy states and optical pulses. Here, to bridge this gap, we propose an improved finite-key analysis of TF-QKD through devising new operator dominance condition. We show that by adding the number of decoy states, the secret key rate can be furtherly improved and approach the asymptotic bound. Our theory can be directly used in TF-QKD experiment to obtain higher secret key rate. Our results can be directly used in experiments to obtain higher key rates.

We propose a mechanism to directly measure the chiral anomaly in disorder Weyl semimetals (WSMs) by the Kondo effect. We find that in a magnetic and electric field driven WSM, the locations of the Kondo peaks can be modulated by the chiral chemical potential, which is proportional to $\mathbf{E}\cdot \mathbf{B}$. The Kondo peaks come from spin fluctuations within the impurities, which apart from the temperature, relate closely to the host's Fermi level. In WSMs, the chiral-anomaly-induced chirality population imbalance will shift the local Fermi levels of the paired Weyl valleys toward opposite directions in energy, and then affects the Kondo effect. Consequently, the Kondo effect can be tunable by an external electric field via the chiral chemical potential. This is unique to the chiral anomaly. Base on this, we argue that the electrically tunable Kondo effect can serve as a direct measurement of the chiral anomaly in WSMs. The Kondo peaks are robust against the disorder effect and therefore, the signal of the chiral anomaly survives for a relatively weak magnetic field., Comment: 7 pages, 4 figures

The intrinsic mechanism on geochemical diversity of high-silica (> 70 wt.% SiO2) granites (HSGs) still remains unclear. In this paper, we focus on the magmatic differentiation of the Shengsi Pluton at the northeastern tip of SE China by an integrated study of geochronology, whole-rock geochemistry and mineral chemistry of zircon and apatite. The Shengsi granites crystallized at ca. 97 Ma, and can be divided into early medium-grained phase (MGP) and late fine-grained phase (FGP). The FGP granites have higher SiO2 (75.0–77.1 wt.%) contents and lower amount of plagioclase, apatite and titanite. The MGP granites likely represent the primary granitic melts and they show transitional geochemical features between I- and A- type granites. In contrast, the FGP granites may represent the melts differentiated from the MGP magma mush and they are characterized by continuously varied to strongly depleted middle rare earth elements (MREEs). Geochemical modeling demonstrates that the varied REEs of the FGP granites are likely controlled by the crystallization/accumulation of titanite, plagioclase and minor zircon during magmatic differentiation. Such a crystal fractionation process in HSGs could be explained by slow “crystal settling” (mainly titanite) in crystal mush induced by dripping solid–liquid mixtures from the magma roof. This work exemplifies the effective crystal fractionation of >70 wt.% SiO2 melts to generate >75 wt.% SiO2 melts in the present coastal area of SE China, and it also highlights the role of slow settling of early crystallized minerals in crystal mush on geochemical diversity of HSGs.

As one major diabetic complication, diabetic nephropathy (DN) has been reported to be associated with various kinds of microRNA (miRNA). Thus, we conducted this study to explore the potential of miR-370 in a rat model of DN through investigation of mesangial cell proliferation and extracellular matrix (ECM). A total of 40 healthy adult male Sprague-Dawley rats were enrolled and assigned into normal (n = 10) and DN ( n = 30, DN rat model) groups. Dual-luciferase reporter assay was performed for the targeting relationship between miR-370 and canopy 1 (CNPY1). Mesangial cells were collected and transfected with prepared mimic, inhibitor or small interfering RNA (siRNA) for analyzing the effect of miR-370 on DN mice with the help of expression and cell biological processes detection. CNPY1 was confirmed as a target gene of miR-370. DN mice had increased expression of miR-370, fibronectin, type I collagen (Col I), type IV collagen (Col IV), and plasminogen activator inhibitor-1 (PAI-1) but reduced CNPY1 expression. Cells transfected with miR-370 mimic and siRNA-CNPY1 had increased expression of fibronectin, Col I, Col IV, and PAI-1 but decreased CNPY1 expression. The miR-370 mimic and siRNA-CNPY1 groups showed increased cell proliferation, as well as elevated ECM accumulation and declined cell apoptosis rate as compared with the blank and negative control groups, with reverse trends observed in the miR-370 inhibitor group. Our study concludes that overexpression of miR-370 promotes mesangial cell proliferation and ECM accumulation by suppressing CNPY1 in a rat model of DN.

Between 1% and 15% of people are globally affected by kidney stones, and this disease has become more common since the 1970s. Therefore, this study aims to investigate the effects of gastrin-releasing peptide receptor (GRPR) gene silencing via the PI3K/Akt signaling pathway on the development of the epithelial-mesenchymal transition (EMT) and formation of a calcium oxalate crystal in renal tubular epithelial cells (TECs) of kidney stones. A total of 70 clean and healthy C57BL/6J mice were assigned into the normal ( n = 10) and kidney stones groups ( n = 60). The underlying regulatory mechanisms of GRPR were analyzed in concert with the treatment of shGRPR-1, LY294002, and shGRPR-1 + LY294002 in TECs isolated from mice with kidney stones. A series of experiments were conducted for the measurement of urinary oxalate and urinary calcium, the renal calcium salt deposition, the positive rate of GRPR, the expressions of renal TECs related genes and calcium oxalate regulation related genes, and the growth of calcium crystals induced by cells. After treatment of shGRPR-1 and shGRPR-1 + LY294002, levels of urinary oxalate and urinary calcium in the serum, as well as positive rate of GRPR, became relatively low, levels of E-cadherin enhanced, whereas levels of Akt, PI3K, GRPR, extents of PI3K and Akt phosphorylation, α-SMA, Vimentin and FSP-1, OPN, MCP-1, and CD44 decreased and a number of crystals reduced. Taken together, we conclude that GRPR gene silencing suppresses the development of the EMT and formation of the calcium oxalate crystal in renal TECs of kidney stones through the inactivation of the PI3K/Akt signaling pathway.

Silicene offers an ideal platform for exploring the phase transition due to strong spin-orbit interaction and its unique structure with strong tunability. With applied electric field and circularly polarized light, silicone is predicted to exhibit rich phases. We propose that these intricate phase transitions can be detected by measuring the bulk Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. We have in detail analyzed the dependence of RKKY interaction on phase parameters for different impurity configurations along zigzag direction. Importantly, we present an interesting comparison between different terms of RKKY interaction with phase diagram. It is found that the in-plane and out-of-plane terms can exhibit the local extreme value or change of sign at the phase critical point and remarkable difference in magnitude for different phase regions. Consequently, the magnetic measurement provides unambiguous signatures to identify various types of phase transition simultaneously, which can be carried out with present technique.

When an electron is incident from a Weyl material to an insulator and totally reflected, it suffers a reflection group delay and a reflection shift (Goos–Hänchen and/or Imbert–Fedorov shifts). We found the group delay is negative for half of the incident states. The negative group delay does not mean the electron is bounced back before its injection, but is an effective acceleration of the electron near the interface induced by self-interference. The reflection shift orients circulating the points at which the surface-bulk state transition occurs. The reflection shift and the group delay cause velocity correction of the bound states in the Weyl material sandwiched by two insulators. The velocity correction features induced by the negative group delay were verified by a tight-binding calculation, in which the concept of group delay is not used.

To improve the density and ablation resistance of ZrB2-SiC coatings, TaSi2 modified ZrB2-SiC coatings was prepared on C/C composites by low-pressure plasma spraying. Systematical investigations about microstructures of two kinds of ceramic coatings were performed by XRD, SEM, EDS, TEM and X-ray computed tomography. The presence of Ta element in the ZrB2-SiC-TaSi2 coating is mainly in the form of fine particles with nanoscale, (Zr0.8Ta0.2)B2, visible fine particles and densification areas. The addition of TaSi2 is conducive to reducing the porosity of the coatings and improving their mechanical and ablation resistance properties.

Granitoids and related mafic microgranular enclaves (MMEs) in continental collision zones may provide crucial insights into the formation and evolution of continental crust. In this paper, we report an investigation into the mineralogy, zircon U–Pb geochronology, whole-rock major and trace elements, and Sr–Nd–Hf isotopic geochemistry of granodiorites and hosted MMEs, as well as monzogranites, from the Zhaxiding intrusive complex in the Gangdese batholith, southern Tibet. Zircon U–Pb dating suggests that these rocks were emplaced during the early Eocene (49 to 47 Ma). Field investigation and petrological observations indicate that the MMEs represent globules of a mafic magma that was injected into the host felsic magma. On the basis of depleted zircon Hf (eHf(t) values of +6.5 to +9.2) and whole-rock Sr–Nd (eNd(t) values of +1.6 to +2.6) isotopic compositions, along with their whole-rock compositions, the MMEs are interpreted as having resulted from mixing of mantle-derived magma with juvenile crust-derived melts. The granodiorites and monzogranites are metaluminous and have positive zircon eHf(t) (+6.3 to +8.9 for granodiorites and +1.7 to +10.2 for monzogranites) and whole-rock eNd(t) (+1.6 to +1.9 for granodiorites and +0.5 to +1.1 for monzogranites) values. The granodiorites further exhibit continental crust-like chemical compositions (e.g., enrichment in Rb, K, and Pb and depletion in Nb and Ta) and high Mg# values, suggesting that they originated from partial melting of juvenile crust with the involvement of mantle-derived melts. However, the monzogranites have lower P, Ti, and total rare earth element contents, similar Rb, Ba, and Sr contents, and uniform Eu anomalies compared with the granodiorites, and were likely generated by fractional crystallization of amphibole and Fe–Ti oxides from juvenile crust-derived magma. We propose that underplating of mantle-derived magma likely triggered coeval crustal magmatism and that mixing of the mantle- and crust-derived magmas and subsequent crystallization differentiation formed the intermediate to felsic Zhaxiding intrusive complex in the Gangdese batholith. The continental crust-like bulk compositions of the intermediate to felsic magmatic rocks represent a net addition of juvenile material to continental crust. Our study thus indicates that magma mixing and differentiation play a significant role in the formation of andesitic to dacitic continental crust in collision zones.

Gabbro–granite complexes that form in active continental margins provide an excellent opportunity to investigate the genetic relationships between acid and basic magmas and offer important insights into crust–mantle interaction. In this paper, we present detailed petrographic, mineralogical, whole-rock geochemical, Sr–Nd isotopic, zircon U–Pb, and Hf isotopic data for the Dongga gabbro–granite complex of the southern Lhasa subterrane, with the aim of elucidating the petrogenesis of these rocks and gaining insights into the processes of crust–mantle interaction associated with the northward subduction of the Neo-Tethyan oceanic slab. The Dongga complex consists predominantly of tonalite and granodiorite with abundant mafic microgranular enclaves (MMEs) and lesser amounts of hornblende gabbro. LA–ICP–MS zircon U–Pb dating yields crystallization ages of 178.0 ± 1.5 Ma and 192.3 ± 1.5 Ma for the hornblende gabbros, and 178.1 ± 1.7 Ma and 178.8 ± 1.8 Ma for the tonalites and MMEs, respectively. Geochemically, the gabbroic rocks have low SiO 2 and Na 2 O + K 2 O concentrations and high Mg# values. These gabbroic rocks are enriched in large ion lithophile elements (LILEs; e.g., Ba, K, Pb, and Sr) and light rare earth elements (LREEs), and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, P, Zr, and Hf). The tonalites are subalkaline and metaluminous and are also characterized by an enrichment of LILEs and LREEs and a depletion of HFSEs. The MMEs are silica poor and alkali rich and have broadly similar trace element signatures to those of the host tonalites. The gabbroic rocks, tonalites, and MMEs have similar initial 87 Sr/ 86 Sr ratios ( I Sr ) of 0.7035–0.7036 and positive e Nd ( t ) values of + 5.3 to + 6.8. However, zircon e Hf ( t ) values from the hornblende gabbros (+ 14.0 to + 18.2) are somewhat higher than those of the tonalites (+ 11.4 to + 15.0) but are similar to the MMEs (+ 14.4 to + 18.2). The combined petrological, geochemical, and isotopic features of the Dongga gabbro–granite complex suggest that the southern Lhasa subterrane was located in an active continental margin setting during the Early Jurassic. The gabbroic rocks were generated by the hydrous partial melting of a depleted mantle wedge metasomatized by aqueous fluids released from the subducted Neo-Tethyan oceanic slab. The tonalites and MMEs were produced by the mixing of mafic magmas related to the gabbroic rocks and felsic magmas derived from the remelting of the newly formed juvenile lower crust. The underplating of mantle-derived magmas and the resulting crustal melting and magma mixing occurred during the Early Jurassic subduction of the Neo-Tethyan oceanic slab. The mantle-derived magmas not only provided substantial heat to melt the lower crust but also mixed with the crust-derived magmas to form granitoids and MMEs.

Three-dimensional Dirac semimetal is an ideal platform in studying topological phase transitions due to its exotic electronic structure. Based on the effective Hamiltonian of material Na3Bi where two degenerated Dirac points are constructed by four Weyl nodes and protected by crystal symmetry, we study its Floquet phase transitions induced by circularly polarized light in off-resonant limit. By breaking the time-reversal symmetry and taking the quadratic momentum into account, abundant phases are realized, including Weyl semimetal, spin-polarized Weyl semimetal (SP-WSM), and normal insulator. The SP-WSM phase is a new phase, in which only pairs of spin-up (or spin-down) opposite-chirality Weyl nodes are remained while the other pairs of spin-down (or spin-up) opposite-chirality Weyl nodes are eliminated. Importantly, all the phase transitions can be manipulated not only by tuning the light intensity but also by changing the incident direction of light. To understand them, we have in detail analyzed the trajectory of Weyl nodes in k space controlled by the circularly polarized light and manifested them with the angle- and spin- dependent Hall conductivity.

Recently discovered Dirac semimetals (DSMs) with two Dirac nodes, such as Na$_{3}$Bi and Cd$_{2}$As$_{3}$, are regarded to carry the $\mathbb{Z}_{2}$ topological charge in addition to the chiral charge. Here, we study the Floquet phase transition of $\mathbb{Z}_{2}$ topological DSMs subjected to a beam of circularly polarized light. Due to the resulting interplay of the chiral and $\mathbb{Z}_{2}$ charges, the Weyl nodes are not only chirality-dependent but also spin-dependent, which constrains the behaviors in creation and annihilation of the Weyl nodes in pair. Interestingly, we find a novel phase: One spinband is in Weyl semimetal phase while the other spinband is in insulator phase, and we dub it Weyl half-metal (WHM) phase. We further study the spin-dependent transport in a Dirac-Weyl semimetal junction and find a spin filter effect as a fingerprint of existence of the WHM phase. The proposed spin filter effect, based on the WHM bulk band, is highly tunable in a broad parameter regime and robust against magnetic disorder, which is expected to overcome the shortcomings of the previously proposed spin filter based on the topological edge/surface states. Our results offer a unique opportunity to explore the potential applications of topological DSMs in spintronics., 6 pages, 4 figures