Quantum spin Hall effect in rutile-based oxide multilayers

Article

关键词: TOPOLOGICAL INSULATORS;    MAJORANA FERMIONS;    TRANSITION;    LATTICE;    STATE;   

DOI  :  10.1103/PhysRevB.94.235111

来源: SCIE

【 摘 要 】

Dirac points in two-dimensional electronic structures are a source for topological electronic states due to the +/-pi Berry phase that they sustain. Here we show that two rutile multilayers [namely (WO2)(2)/(ZrO2)(n) and (PtO2)(2)/(ZrO2)(n)], where an active bilayer is sandwiched by a thick enough (n = 6 is sufficient) band insulating substrate, show semimetallic Dirac dispersions with a total of four Dirac cones along the Gamma - M direction. These become gapped upon the introduction of spin-orbit coupling, giving rise to an insulating ground state comprising four edge states. We discuss the origin of the lack of topological protection in terms of the valley spin-Chern numbers and the multiplicity of Dirac points. We show with a model Hamiltonian that mirror-symmetry breaking would be capable of creating a quantum phase transition to a strong topological insulator, with a single Kramers pair per edge.

【 授权许可】

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