Department of Physics, Cornell University, Ithaca, New York 14853, USA.
Department of Physics, Stanford University, Stanford, California 94305-4060, USA.
Nat Commun. 2017 Apr 11;8:14985. doi: 10.1038/ncomms14985.
Theoretically, it has been known that breaking spin degeneracy and effectively realizing spinless fermions is a promising path to topological superconductors. Yet, topological superconductors are rare to date. Here we propose to realize spinless fermions by splitting the spin degeneracy in momentum space. Specifically, we identify monolayer hole-doped transition metal dichalcogenide (TMD)s as candidates for topological superconductors out of such momentum-space-split spinless fermions. Although electron-doped TMDs have recently been found superconducting, the observed superconductivity is unlikely topological because of the near spin degeneracy. Meanwhile, hole-doped TMDs with momentum-space-split spinless fermions remain unexplored. Employing a renormalization group analysis, we propose that the unusual spin-valley locking in hole-doped TMDs together with repulsive interactions selectively favours two topological superconducting states: interpocket paired state with Chern number 2 and intrapocket paired state with finite pair momentum. A confirmation of our predictions will open up possibilities for manipulating topological superconductors on the device-friendly platform of monolayer TMDs.
从理论上讲，打破自旋简并并有效地实现无自旋费米子是实现拓扑超导体的一条有前途的途径。然而，迄今为止拓扑超导体仍然很少见。在这里，我们提出通过在动量空间中分裂自旋简并来实现无自旋费米子。具体来说，我们确定单层空穴掺杂过渡金属二卤代物（TMD）是这种动量空间分裂的无自旋费米子的拓扑超导体的候选者。尽管最近已经发现电子掺杂的 TMD 具有超导性，但由于近自旋简并，观察到的超导性不太可能是拓扑的。同时，具有动量空间分裂的无自旋费米子的空穴掺杂 TMD 仍未被探索。利用重整化群分析，我们提出空穴掺杂 TMD 中的异常自旋-谷锁定以及排斥相互作用特别有利于两种拓扑超导态：口袋间配对态（Chern 数为 2）和口袋内配对态（具有有限对动量）。对我们预测的确认将为在单层 TMD 设备友好的平台上操纵拓扑超导体开辟可能性。
