Li Leiqiang, Zhang Shunhong, Hu Guojing, Guo Linhai, Wei Tong, Qin Wei, Xiang Bin, Zeng Changgan, Zhang Zhenyu, Cui Ping
International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nano Lett. 2022 Aug 24;22(16):6767-6774. doi: 10.1021/acs.nanolett.2c02422. Epub 2022 Aug 5.
Two-dimensional transition metal dichalcogenides possessing superconductivity and strong spin-orbit coupling exhibit high in-plane upper critical fields due to Ising pairing. Yet to date, whether such systems can become topological Ising superconductors remains to be materialized. Here we show that monolayered NbSe can be converted into Ising superconductors with nontrivial band topology via physical or chemical pressuring. Using first-principles calculations, we first demonstrate that a hydrostatic pressure higher than 2.5 GPa can induce a - band inversion, rendering nontrivial band topology to NbSe. We then illustrate that Te-doping can function as chemical pressuring in inducing nontrivial topology in NbSeTe with ≥ 0.8, due to a larger atomic radius and stronger spin-orbit coupling of Te. We also evaluate the upper critical fields within both approaches, confirming the enhanced Ising superconductivity nature, as experimentally observed. Our findings may prove to be instrumental in material realization of topological Ising superconductivity in two-dimensional systems.
具有超导性和强自旋轨道耦合的二维过渡金属二硫属化物由于伊辛配对而表现出较高的面内上临界场。然而迄今为止，此类体系能否成为拓扑伊辛超导体仍有待实现。在此我们表明，通过物理或化学施压，单层NbSe₂可转变为具有非平凡能带拓扑结构的伊辛超导体。利用第一性原理计算，我们首先证明高于2.5 GPa的静水压力可诱导能带反转，赋予NbSe₂非平凡的能带拓扑结构。然后我们说明，由于Te的原子半径较大且自旋轨道耦合更强，当Te含量≥0.8时，Te掺杂可作为化学施压手段在NbSe₂₋ₓTe中诱导非平凡拓扑结构。我们还评估了两种方法中的上临界场，证实了如实验观测到的增强的伊辛超导性质。我们的发现可能有助于二维体系中拓扑伊辛超导性的材料实现。
