Classification of Critical Points in Energy Bands Based on Topology, Scaling and Symmetry
ORAL
Abstract
A critical point of the energy dispersion is the momentum where electron velocity vanishes. At
the corresponding energy, the density of states (DOS) exhibits non-analyticity such as divergence.
Critical points can be rst classied as ordinary and high-order ones, and the ordinary critical
points have been studied thoroughly by Leon van Hove, whose DOS is particle-hole symmetric and
logarithmically divergent. In this work, we describe and classify high-order critical points based
on topology, scaling and symmetry. We show that high-order critical points can have power-law
divergent DOS with particle-hole asymmetry, and can be realized at generic or symmetric momenta
by tuning a few parameters such as twist angle, strain, pressure and/or external elds.
the corresponding energy, the density of states (DOS) exhibits non-analyticity such as divergence.
Critical points can be rst classied as ordinary and high-order ones, and the ordinary critical
points have been studied thoroughly by Leon van Hove, whose DOS is particle-hole symmetric and
logarithmically divergent. In this work, we describe and classify high-order critical points based
on topology, scaling and symmetry. We show that high-order critical points can have power-law
divergent DOS with particle-hole asymmetry, and can be realized at generic or symmetric momenta
by tuning a few parameters such as twist angle, strain, pressure and/or external elds.
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Presenters
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Noah Yuan
Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology
Authors
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Noah Yuan
Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology
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Liang Fu
Massachusetts Institute of Technology, Massachusetts Institute of Technology MIT, Department of Physics, Massachusetts Institute of Technology MIT, Physics, MIT, Physics, Massachusetts Institute of Technology, MIT