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arXiv · 1507.01742

Emergence of a Chern-insulating state from a semi-Dirac dispersion

Huaqing Huang·Zhirong Liu·Hongbin Zhang·Wenhui Duan·David Vanderbilt
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Abstract

A Chern insulator (quantum anomalous Hall insulator) phase is demonstrated to exist in a typical semi-Dirac system, the TiO2/VO2 heterostructure. By combining first-principles calculations with Wannier-based tight-binding model, we calculate the Berry curvature distribution, finding a Chern number of -2 for the valence bands, and demonstrate the existence of gapless chiral edge states, ensuring quantization of the Hall conductivity to 2e^2/h. A new semi-Dirac model, where each semi-Dirac cone is formed by merging three conventional Dirac points, is proposed to reveal how the nontrivial topology with finite Chern number is compatible with a semi-Dirac electronic spectrum.

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Huaqing Huang, Zhirong Liu, Hongbin Zhang, Wenhui Duan, David Vanderbilt. 2015-07-07. Emergence of a Chern-insulating state from a semi-Dirac dispersion. https://doi.org/10.1103/physrevb.92.161115

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