Topological phases of Bi(111) bilayer in an external exchange field

Zhang, H.; Freimuth, F.; Bihlmayer, G.; Mokrousov, Y.; Blügel, S.

doi:10.1103/PhysRevB.86.035104

Journal Article

PreJuSER-22138

Topological phases of Bi(111) bilayer in an external exchange field

Zhang, H.FZJ* ; Freimuth, F.FZJ* ; Bihlmayer, G.FZJ* ; Blügel, S.FZJ* ; Mokrousov, Y.FZJ*

2012
APS College Park, Md.

Physical review / B 86(3), 035104 (2012) [10.1103/PhysRevB.86.035104]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10857 doi:10.1103/PhysRevB.86.035104

Abstract: Using first-principles methods, we investigate topological phase transitions as a function of exchange field in a Bi(111) bilayer. Evaluation of the spin Chern number for different magnitudes of the exchange field reveals that when the time-reversal symmetry is broken by a small exchange field, the system enters the time-reversal broken topological insulator phase, introduced by Yang et al. [Phys. Rev. Lett. 107, 066602 (2011)]. After a metallic phase in the intermediate region, the quantum anomalous Hall phase with a nonzero Chern number emerges at a sufficiently large exchange field. We analyze the phase diagram from the viewpoint of the evolution of the electronic structure, edge states, and transport properties and demonstrate that different topological phases can be distinguished by the spin polarization of the edge states as well as spin or charge transverse conductivity.

Keyword(s): J

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Physics, Condensed Matter

Note: We acknowledge very helpful discussions with Emil Prodan, Sheng Li, Klaus Koepernik, and Marjana Lezaic. This work was supported by the HGF-YIG Programme VH-NG-513 and by the DFG through Research Unit 912 and Grant No. HE3292/7-1. Computational resources were provided by the Julich Supercomputing Centre.

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