Bulk quantum Hall effect of spin-valley coupled Dirac fermions in the polar antiferromagnet BaMnSb2

Article

关键词: INITIO MOLECULAR-DYNAMICS;    TOTAL-ENERGY CALCULATIONS;    SINGLE-CRYSTALS;    BERRYS PHASE;    TRANSITION;    GROWTH;    FIELD;   

DOI  :  10.1103/PhysRevB.101.081104

来源: SCIE

【 摘 要 】

Unconventional features of relativistic Dirac/Weyl quasiparticles in topological materials are most evidently manifested in the two-dimensional quantum Hall effect (QHE), whose variety is further enriched by their spin and/or valley polarization. Although its extension to three dimensions has been long sought and inspired theoretical proposals, material candidates have been lacking. Here, we have discovered valley-contrasting spin-polarized Dirac fermions in a multilayer form in the bulk antiferromagnet BaMnSb2, where out-of-plane Zeeman-type spin splitting is induced by in-plane inversion symmetry breaking and spin-orbit coupling in the distorted Sb square net. Furthermore, we have observed well-defined quantized Hall plateaus together with vanishing interlayer conductivity at low temperatures as a hallmark of the half-integer QHE in a bulk form. The Hall conductance of each layer is found to be nearly quantized to 2(N + 1/2)e(2)/h, with N being the Landau index, which is consistent with two spin-polarized Dirac valleys protected by the strong spin-valley coupling.

【 授权许可】

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