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arXiv · 2009.12890

Giant Anomalous Hall Effect due to Double-Degenerate Quasi Flat Bands

Wei Jiang·Duarte J. P. de Sousa·Jian-Ping Wang·Tony Low
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Abstract

We propose a novel approach to achieve giant AHE in materials with flat bands (FBs). FBs are accompanied by small electronic bandwidths, which consequently increases the momentum separation ($K$) within pair of Weyl points and thus the integrated Berry curvature. Starting from a simple model with a single pair of Weyl nodes, we demonstrated the increase of $K$ and AHE by decreasing bandwidth. It is further expanded to a realistic pyrochlore lattice model with characteristic double degenerated FBs, where we discovered a giant AHE while maximizing the $K$ with nearly vanishing band dispersion of FBs. We identify that such model system can be realized in both pyrochlore and spinel compounds based on first-principles calculations, validating our theoretical model and providing a feasible platform for experimental exploration.

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Wei Jiang, Duarte J. P. de Sousa, Jian-Ping Wang, Tony Low. 2020-09-27. Giant Anomalous Hall Effect due to Double-Degenerate Quasi Flat Bands. https://doi.org/10.1103/physrevlett.126.106601

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