Visualizing near-coexistence of massless Dirac electrons and ultra-massive saddle point electrons
Abstract
Strong singularities in the electronic density of states amplify correlation effects and play a key role in determining the ordering instabilities in various materials. Recently high order van Hove singularities (VHSs) with diverging power-law scaling have been classified in single-band electron models. We show that the 110 surface of Bismuth exhibits high order VHS with an usually high density of states divergence . Detailed mapping of the surface band structure using scanning tunneling microscopy and spectroscopy combined with first-principles calculations show that this singularity occurs in close proximity to Dirac bands located at the center of the surface Brillouin zone. The enhanced power-law divergence is shown to originate from the anisotropic flattening of the Dirac band just above the Dirac node. Such near-coexistence of massless Dirac electrons and ultra-massive saddle points enables to study the interplay of high order VHS and Dirac fermions.
Keywords
Cite
@article{arxiv.2303.02250,
title = {Visualizing near-coexistence of massless Dirac electrons and ultra-massive saddle point electrons},
author = {Abhay Kumar Nayak and Jonathan Reiner and Hengxin Tan and Huixia Fu and Henry Ling and Chandra Shekhar and Claudia Felser and Tami Pereg-Barnea and Binghai Yan and Haim Beidenkopf and Nurit Avraham},
journal= {arXiv preprint arXiv:2303.02250},
year = {2023}
}