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arXiv · 1706.02294

Chiral Flat Bands: Existence, Engineering and Stability

Ajith Ramachandran·Alexei Andreanov·Sergej Flach
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Abstract

We study flat bands in bipartite tight-binding networks with discrete translational invariance. Chiral flat bands with chiral symmetry eigenenergy E = 0 and host compact localized eigenstates for finite range hopping. For a bipartite network with a majority sublattice chiral flat bands emerge. We present a simple generating principle of chiral flat band networks and as a showcase add to the previously observed cases a number of new potentially realizable chiral flat bands in various lattice dimensions. Chiral symmetry respecting network perturbations - including disorder and synthetic magnetic fields - preserve both the flatband and the modified compact localized states. Chiral flatbands are spectrally protected by gaps, and pseudogaps in the presence of disorder due to Griffiths effects.

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Ajith Ramachandran, Alexei Andreanov, Sergej Flach. 2017-06-07. Chiral Flat Bands: Existence, Engineering and Stability. https://doi.org/10.1103/physrevb.96.161104

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