Topological Insulators and Nematic Phases from Spontaneous Symmetry Breaking in 2D Fermi Systems with a Quadratic Band Crossing

被引：383

作者：

Sun, Kai ^{[1
]}

Yao, Hong ^{[2
]}

Fradkin, Eduardo ^{[1
]}

Kivelson, Steven A. ^{[2
]}

机构：

[1] Univ Illinois, Dept Phys, Urbana, IL 61801 USA

[2] Stanford Univ, Dept Phys, Stanford, CA 94305 USA

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 103卷 / 04期

基金：

美国国家科学基金会;

关键词：

HGTE QUANTUM-WELLS; SUPERCONDUCTORS; LATTICE;

D O I：

10.1103/PhysRevLett.103.046811

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We investigate the stability of a quadratic band-crossing point (QBCP) in 2D fermionic systems. At the noninteracting level, we show that a QBCP exists and is topologically stable for a Berry flux +/- 2 pi if the point symmetry group has either fourfold or sixfold rotational symmetries. This putative topologically stable free-fermion QBCP is marginally unstable to arbitrarily weak short-range repulsive interactions. We consider both spinless and spin-1/2 fermions. Four possible ordered states result: a quantum anomalous Hall phase, a quantum spin Hall phase, a nematic phase, and a nematic-spin-nematic phase.

引用

页数：4

共 28 条

[1] Quantum spin Hall effect and topological phase transition in HgTe quantum wells [J].