Phase diagram of the ?=2 quantum Hall state in bilayer graphene

被引：6

作者：

Khanna, Udit ^{[1
]}

Huang, Ke ^{[2
]}

Murthy, Ganpathy ^{[3
]}

Fertig, H. A. ^{[4
]}

Watanabe, Kenji ^{[5
]}

Taniguchi, Takashi ^{[6
]}

Zhu, Jun ^{[2
]}

Shimshoni, Efrat ^{[1
]}

机构：

[1] Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel

[2] Penn State Univ, Dept Phys, University Pk, PA 16802 USA

[3] Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA

[4] Indiana Univ, Dept Phys, Bloomington, IN 47405 USA

[5] Natl Inst Mat Sci, Res Ctr Funct Mat, 1-1 Namiki, Tsukuba 3050044, Japan

[6] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, 1-1 Namiki, Tsukuba 3050044, Japan

来源：

PHYSICAL REVIEW B | 2023年 / 108卷 / 04期

基金：

美国国家科学基金会; 以色列科学基金会;

关键词：

BROKEN-SYMMETRY; SPIN;

D O I：

10.1103/PhysRevB.108.L041107

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Bilayer graphene exhibits a rich phase diagram in the quantum Hall regime, arising from a multitude of internal degrees of freedom, including spin, valley, and orbital indices. The variety of fractional quantum Hall states between filling factors 1 < v = 2 suggests, among other things, a quantum phase transition between valleyunpolarized and polarized states at a perpendicular electric-field D*. We find that the behavior of D* with v changes markedly as B is reduced. At v = 2, D* may even vanish when B is sufficiently small. We present a theoretical model for lattice-scale interactions, which explains these observations; surprisingly, both repulsive and attractive components in the interactions are required. Within this model, we analyze the nature of the v = 2 state as a function of the magnetic and electric fields and predict that valley coherence may emerge for D & SIM; D* in the high-B regime. This suggests the system supports Kekule bond ordering, which could, in principle, be verified via scanning tunneling measurements.

引用

页数：7

共 53 条

[1] Graphene integer quantum Hall effect in the ferromagnetic and paramagnetic regimes [J].