Time-reversal invariant topological moiré flat band: A platform for the fractional quantum spin Hall effect

被引：8

作者：

Wu, Yi-Ming ^{[1
]}

Shaffer, Daniel ^{[2
]}

Wu, Zhengzhi ^{[3
]}

Santos, Luiz H. ^{[2
]}

机构：

[1] Stanford Univ, Stanford Inst Theoret Phys, Stanford, CA 94305 USA

[2] Emory Univ, Dept Phys, 400 Dowman Dr, Atlanta, GA 30322 USA

[3] Tsinghua Univ, Inst Adv Study, Beijing 100084, Peoples R China

来源：

PHYSICAL REVIEW B | 2024年 / 109卷 / 11期

关键词：

MAGIC-ANGLE; CORRELATED STATES; TRANSITION; INSULATOR; MOTT; SUPERCONDUCTIVITY;

D O I：

10.1103/PhysRevB.109.115111

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Motivated by recent observation of the quantum spin Hall effect in monolayer germanene and twisted bilayer transition -metal dichalcogenides (TMDs), we study the topological phases of moir & eacute; twisted bilayers with time -reversal symmetry and spin s z conservation. By using a continuum model description, which can be applied to both germanene and TMD bilayers, we show that at small twist angles the emergent moir & eacute; flat bands can be topologically nontrivial due to inversion symmetry breaking. Each of these flat bands admits a lowest -Landau -level description for each spin projection in the chiral limit and at magic twist angle. This allows for the construction of a many -body Laughlin state with time -reversal symmetry, which can be stabilized by a short-range pseudopotential, and therefore serves as an ideal platform for realizing the so -far elusive fractional quantum spin Hall effect with emergent spin -1 / 2 U(1) symmetry.

引用

页数：11

共 104 条

[1]

[Anonymous], The sublattice weight for the nth band is defined as u(n) E A/B = I |u(A/B) I,n |2 where u(A/B) I,n is the eigenstate for the nth band projected to A/B sublattice and I is the shorthand of the indices other than sublattice

[2]

[Anonymous], One caveat here is that chistau,k is a two-component wavefunction, with each component from distinct layers shifted by q1 from each other. Bloch's theorem for chistau thus implies chistau,k(r + a) = eikadiag(1, eiq1a)chistau,k(r).

[3]

[Anonymous], Here we approximately assume that is the same for both layers

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