Excited quantum Hall effect: enantiomorphic flat bands in a Yin-Yang Kagome lattice
ORAL
Abstract
Quantum Hall effect (QHE) is one of the most fruitful research topics in condensed-matter physics. Ordinarily, the QHE manifests in a ground state with time-reversal symmetry broken by magnetization to carry a quantized chiral edge conductivity around a two-dimensional insulating bulk. We propose a theoretical concept and model of non-equilibrium excited-state QHE (EQHE) without intrinsic magnetization. It arises from circularly polarized photoexcitation between two enantiomorphic flat bands of opposite chirality, each supporting originally a helical topological insulating state hosted in a Yin-Yang Kagome lattice. The chirality of its edge state can be reversed by the handedness of light, instead of the direction of magnetization as in the conventional quantum (anomalous) Hall effect, offering a simple switching mechanism for quantum devices. Implications and realization of EQHE in real materials are discussed.
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Presenters
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Yinong Zhou
University of Utah
Authors
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Yinong Zhou
University of Utah
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Gurjyot Sethi
University of Utah, Materials Science and Engineering, University of Utah
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Hang Liu
University of Utah
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Zhengfei Wang
University of Science and Technology of China
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Feng Liu
Utah University, University of Utah, Department of Materials Science and Engineering, University of Utah, Materials Science and Engineering, University of Utah