Fermi surface induced lattice distortion in NbTe$_2$

TL;DR

This paper investigates how Fermi surface nesting and electron-phonon interactions induce lattice distortion and charge density wave formation in NbTe₂, combining experimental and theoretical approaches to elucidate the underlying mechanisms.

Contribution

It provides a comprehensive analysis linking Fermi surface features to lattice distortion in NbTe₂ using ARPES and ab initio calculations, highlighting the role of electron-phonon coupling.

Findings

Fermi surface is pseudogapped over large regions

Fermi surface nesting and electron-phonon coupling drive distortion

Charge density wave phase is stabilized by these interactions

Abstract

The origin of the monoclinic distortion and domain formation in the quasi two-dimensional layer compound NbTe$_2$ is investigated. Angle-resolved photoemission shows that the Fermi surface is pseudogapped over large portions of the Brillouin zone. Ab initio calculation of the electron and phonon bandstructure as well as the static RPA susceptibility lead us to conclude that Fermi surface nesting and electron-phonon coupling play a key role in the lowering of the crystal symmetry and in the formation of the charge density wave phase.