Topological phases in pseudospin-1 Fermi gases with two-dimensional spin-orbit coupling
Topological phases in pseudospin-1 Fermi gases with two-dimensional spin-orbit coupling
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DOI：
10.1103/physreva.101.053613
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发表时间：
2018-09
影响因子：
2.9
通讯作者：
Junpeng Hou;Haiping Hu;Chuanwei Zhang
中科院分区：
文献类型：
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作者：
Junpeng Hou;Haiping Hu;Chuanwei Zhang
最近超冷玻色子和费米子的自旋-轨道(SO)耦合的实验实现，为工程量子物质开辟了一条激动人心的途径，这可能是在固态材料中实现的挑战，例如SO耦合的伪自旋-1费米子。虽然自旋-1玻色子的一维SO耦合已经在实验上实现，但二维SO耦合的产生及其拓扑性质还没有得到很大的探索。本文提出了在正方形晶格中实现赝旋-1费米气体的二维Rashba型SO耦合的实验方案。由于扩展的自旋自由度，许多有趣的拓扑相可以不依赖于在固态材料中至关重要的点群对称性而存在。这些奇特的相包括三重简并点、二次带接触、具有五个Majorana模的大陈数($C=5)超流体、三重Weyl费米子等。我们的方案可以推广到更大的自旋，并为利用大的自旋自由度而不是特定的晶格对称性来设计拓扑量子物质提供了一条独特的路线。
The recent experimental realization of spin-orbit (SO) coupling for ultracold bosons and fermions opens an exciting avenue for engineering quantum matter that may be challenging to realize in solid-state materials such as SO-coupled pseudospin-1 fermions. While one-dimensional SO coupling for spin-1 bosons has been experimentally realized, the generation of two-dimensional (2D) SO coupling and its topological properties are largely unexplored. Here we propose an experimental scheme for realizing a 2D Rashba-type SO coupling in a square lattice for pseudospin-1 Fermi gases. Because of the extended spin degree of freedom, many interesting topological phases could exist without relying on lattice point group symmetries that are crucial in solid-state materials. These exotic phases include triply degenerate points, quadratic band touching, a large Chern number ($C=5$) superfluid with five Majorana modes, triple-Weyl fermions, and so on. Our scheme can be generalized to larger spins and provides a distinctive route for engineering topological quantum matter by utilizing large spin degrees of freedom, instead of specific lattice symmetries.