Higher-order Van Hove singularity in magic-angle twisted trilayer graphene

Daniele Guerci,Christophe Mora,Pascal Simon

doi:10.1103/physrevresearch.4.l012013

Abstract

The authors use symmetry arguments to show a higher-order Van Hove singularity in mirror-symmetric twisted trilayer graphene, which is tuned by varying the twist angle and a perpendicular electric field by gating.

Highlights

Strong correlations generally result from a quenching of electronic motion, comparatively magnifying the strength of electron-electron interactions
We have found that Twisted trilayer graphene (TTG) hosts a zero-energy higher-order Van Hove singularity with an exponent −1/3 that is stronger than the one predicted in twisted bilayer graphene
We derived the existence of a higher-order Van Hove singularity (VHS) in mirror-symmetric TTG associated with a strong zero-energy peak in the density of states

Summary

Introduction

Strong correlations generally result from a quenching of electronic motion, comparatively magnifying the strength of electron-electron interactions. Conventional Van Hove singularities entail a logarithmic singularity, but there are higher-order types [3,4] with more diverging power-law scaling which have been recently classified in single-band electron models [5,6]. In this Letter, we argue that a strong higher-order Van Hove singularity emerges in the single-particle spectrum of TTG upon tuning the displacement field and rotation angle. It results from the symmetric merging at zero energy of two standard VHS with opposite energies.

Published by the American Physical Society

Conclusions