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arXiv · 1011.4504

Robust Level Coincidences in the Subband Structure of Quasi 2D Systems

R. Winkler·L. Y. Wang·Y. H. Lin·C. S. Chu
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Abstract

Recently, level crossings in the energy bands of crystals have been identified as a key signature for topological phase transitions. Using realistic models we show that the parameter space controlling the occurrence of level coincidences in energy bands has a much richer structure than anticipated previously. In particular, we identify robust level coincidences that cannot be removed by a small perturbation of the Hamiltonian compatible with the crystal symmetry. Different topological phases that are insulating in the bulk are then separated by a gapless (metallic) phase. We consider HgTe/CdTe quantum wells as a specific example.

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R. Winkler, L. Y. Wang, Y. H. Lin, C. S. Chu. 2011-03-11. Robust Level Coincidences in the Subband Structure of Quasi 2D Systems. https://doi.org/10.1016/j.ssc.2012.09.002

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