The Role of GmSnRK1-GmNodH Module in Regulating Soybean Nodulation Capacity.

SnRK1 protein kinase plays hub roles in plant carbon and nitrogen metabolism. However, the function of SnRK1 in legume nodulation and symbiotic nitrogen fixation is still elusive. In this study, we identified GmNodH, a putative sulfotransferase, as an interacting protein of GmSnRK1 by yeast two-hybrid screen. The qRT-PCR assays indicate that GmNodH gene is highly expressed in soybean roots and could be induced by rhizobial infection and nitrate stress. Fluorescence microscopic analyses showed that GmNodH was colocalized with GsSnRK1 on plasma membrane. The physical interaction between GmNodH and GmSnRK1 was further verified by using split-luciferase complementary assay and pull-down approaches. In vitro phosphorylation assay showed that GmSnRK1 could phosphorylate GmNodH at Ser193. To dissect the function and genetic relationship of GmSnRK1 and GmNodH in soybean, we co-expressed the wild-type and mutated GmSnRK1 and GmNodH genes in soybean hairy roots and found that co-expression of GmSnRK1/GmNodH genes significantly promoted soybean nodulation rates and the expression levels of nodulation-related GmNF5α and GmNSP1 genes. Taken together, this study provides the first biological evidence that GmSnRK1 may interact with and phosphorylate GmNodH to synergistically regulate soybean nodulation.

Signatures of nontrivial Rashba metal states in a transition metal dichalcogenides Josephson junction.

Nontrivial Rashba metal states in conventional semiconductor materials generated by both Rashba spin-orbit coupling and ferromagnetic exchange coupling coexisting were recently predicted and exploited. Single layered transition metal dichalcogenides (TMDC) featuring those states and their potential applications have been less focused. We find that, in the materials with Rashba spin-orbit coupling only, nontrivial Rashba metallic states can be manipulated by an external gate voltage. Based on extensive numerical simulations, the relationships between the supercurrent and nontrivial Rashba metallic states in the TMDC Josephson junction have been investigated. It is shown that, in the absence of the Rashba spin-orbit coupling, the critical supercurrent exhibits a stark difference between normal Rashba metal state and anomalous Rashba metal state in the finite junction as compared to the case of the short junction. While in the case of the finite Rashba spin-orbit coupling, the critical supercurrent demonstrates a reentrant behavior when Fermi level sweeps from anomalous Rashba metal state to Rashba ring metal state. Intriguingly, not only at the conversion of the nontrivial Rashba metallic states but also in the Rashba ring metal state the reentrant behavior exhibits again, which could be well explained by the mixing of spin-triplet Cooper pairs with spin-singlet Cooper pairs in Ising superconductor. Such a reentrant effect offers a new way to detect Ising superconductivity based on the TMDC systems. Meanwhile our study also clarified that the nontrivial Rashba metallic state plays an important role in controlling the supercurrent in the TMDC Josephson junction, which is useful for designing future superconducting devices.

Andreev reflection in nodal-line Weyl semimetal.

Based on the Bogoliubov-de Gennes equation, the quantum scattering problem through a nodal-line Weyl semimetal based normal metal/superconductor heterojunction has been theoretically studied. Since the crystallographic anisotropy in the material, two different orientations between the crystalline axis and the superconducting interface have been revealed. Considering a heterojunction with the interface paralleling to the basal plane, it is found that Andreev reflection with [Formula: see text] due to Klein-like scattering gives rise to a perfect scattering. Deviation from the critical value, Andreev reflection falls down and normal reflection goes up. While the interface is perpendicular to the basal plane, the pure intra-mode retro-Andreev reflection (RAR) and inter-mode specular Andreev reflection (SAR) are manifested at the normal incident. Moreover, the reflection coefficient exhibits the reentrant behavior with the Fermi energy. Fundamentally, such features are a consequence of the torus-like iso-energy surfaces of the nodal-line Weyl semimetals, which is in sharp contrast to the case of conventional materials, graphene, and Weyl-point semimetals. Those novel scattering processes also result in a distinctive tunneling conductance, such as the sub-gap nonmonotonic features, the interface directional dependent zero bias conductances and the reentrant behavior, which can be served as a smoking gun to distinguish the mode-resolved Andreev reflections in experiments.

Retro-normal reflection and specular Andreev reflection in a transition metal dichalcogenides superconducting heterojunction.

Based on the Bogoliubov-de Gennes equation, the spin-resolved scattering problem through a transition metal dichalcogenides normal metal/superconductor has been investigated. It is shown that the tunneling conductances have a close relationship with the nontrivial Rashba metallic states. Without the Rashba spin-orbit interaction (RSOI), the tunneling conductances exhibit clear characteristic features for detecting the normal Rashba metal state (NRMS) and the anomalous Rashba metal state (ARMS). While in the presence of RSOI, the oscillation, hump structure, and the reentrant behavior of the tunneling conductances can be served as a smoking gun to distinguish the Rashba ring metal state (RRMS) from those nontrivial metallic states. Fundamentally, in sharp contrast to the NRMS and the ARMS where only the normal reflection and the retro-Andreev reflection can occur, the additional scattering processes of the retro-normal reflection (RNR) and the specular Andreev reflection (SAR) can take place in the present junction with the RRMS. Thus the obtained results offer a feasible way to determine the RNR, the SAR, and the nontrivial Rashba metallic states based on the transition metal dichalcogenides superconducting heterojunction.

Giant magnetoresistance control and nontrivial metallic state manipulation in a transition-metal dichalcogenide spin-valve using a gate voltage.

Here, we have theoretically studied the valley- and spin-resolved transport in a monolayer transition metal dichalcogenides based spin valve device, where both the Rashba spin orbit interaction and a gate voltage coexist in the central lead. In contrast to conventional semiconductor, nontrivial metallic states, such as, normal Rashba metal state (NRMS), anomalous Rashba metal state (ARMS), and Rashba ring metal state (RRMS), can be generated and manipulated by Rashba spin orbit interaction without the magnetic effect. For a nonferromagnetic double junction, it was found that the valley- and spin-resolved tunneling conductance can be effectively tuned by the incident energy, the junction length, the Rashba spin orbit interaction strength, and the gate voltage. Due to the spin texture and the Fermi wavevectors in the central lead, both the tunneling coefficient and the tunneling conductance all exhibit the remarkable characteristic features which enable us to diagnose the special states. For a ferromagnetic spin valve device, the resulting nontrivial metallic groundstates in the central lead also demonstrate directly in the giant magnetoresistance with notable unique features. We have further revealed that a perfect valley and spin giant magnetoresistance stems from the spin splitting and the spin-valley coupling. These valley- and spin-resolved phenomena are interesting for both fundamental research and applications.

Shot noise and electronic properties in the inversion-symmetric Weyl semimetal resonant structure.

Using the transfer matrix method, the authors combine the analytical formula with numerical calculation to explore the shot noise and conductance of massless Weyl fermions in the Weyl semimetal resonant junction. By varying the barrier strength, the structure of the junction, the Fermi energy, and the crystallographic angle, the shot noise and conductance can be tuned efficiently. For a quasiperiodic superlattice, in complete contrast to the conventional junction case, the effect of the disorder strength on the shot noise and conductance depends on the competition of classical tunneling and Klein tunneling. Moreover, the delta barrier structure is also vital in determining the shot noise and conductance. In particular, a universal Fano factor has been found in a single delta potential case, whereas the resonant structure of the Fano factor perfectly matches with the number of barriers in a delta potential superlattice. These results are crucial for engineering nanoelectronic devices based on this topological semimetal material.

A proposed experimental diagnosing of specular Andreev reflection using the spin orbit interaction.

Based on the Dirac-Bogoliubov-de Gennes equation, we theoretically investigate the chirality-resolved transport properties through a superconducting heterojunction in the presence of both the Rashba spin orbit interaction (RSOI) and the Dresselhaus spin orbit interaction (DSOI). Our results show that, if only the RSOI is present, the chirality-resolved Andreev tunneling conductance can be enhanced in the superconducting gap, while it always shows a suppression effect for the case of the DSOI alone. In contrast to the similar dependence of the specular Andreev zero bias tunneling conductance on the SOI, the retro-Andreev zero bias tunneling conductance exhibit the distinct dependence on the RSOI and the DSOI. Moreover, the zero-bias tunneling conductances for the retro-Andreev reflection (RAR) and the specular Andreev reflection (SAR) also show a qualitative difference with respect to the barrier parameters. When the RSOI and the DSOI are finite, three orders of magnitude enhancement of specular Andreev tunneling conductance is revealed. Furthermore, by analyzing the balanced SOI case, we find that the RAR is in favor of a parabolic dispersion, but a linear dispersion is highly desired for the SAR. These results shed light on the diagnosing of the SAR in graphene when subjected to both kinds of SOI.

Chiral tunneling in gated inversion symmetric Weyl semimetal.

Based on the chirality-resolved transfer-matrix method, we evaluate the chiral transport tunneling through Weyl semimetal multi-barrier structures created by periodic gates. It is shown that, in sharp contrast to the cases of three dimensional normal semimetals, the tunneling coefficient as a function of incident angle shows a strong anisotropic behavior. Importantly, the tunneling coefficients display an interesting periodic oscillation as a function of the crystallographic angle of the structures. With the increasement of the barriers, the tunneling current shows a Fabry-Perot type interferences. For superlattice structures, the fancy miniband effect has been revealed. Our results show that the angular dependence of the first bandgap can be reduced into a Lorentz formula. The disorder suppresses the oscillation of the tunneling conductance, but would not affect its average amplitude. This is in sharp contrast to that in multi-barrier conventional semiconductor structures. Moreover, numerical results for the dependence of the angularly averaged conductance on the incident energy and the structure parameters are presented and contrasted with those in two dimensional relativistic materials. Our work suggests that the gated Weyl semimetal opens a possible new route to access to new type nanoelectronic device.

Gate-tuned Josephson effect on the surface of a topological insulator.

In the study, we investigate the Josephson supercurrent of a superconductor/normal metal/superconductor junction on the surface of a topological insulator, where a gate electrode is attached to the normal metal. It is shown that the Josephson supercurrent not only can be tuned largely by the temperature but also is related to the potential and the length of the weak-link region. Especially, the asymmetry excess critical supercurrent, oscillatory character, and plateau-like structure have been revealed. We except those phenomena that can be observed in the recent experiment.