Spectral properties of incommensurate charge-density wave systems

TL;DR

This paper investigates how incommensurate charge-density waves affect the electronic structure of high-temperature cuprates, revealing local gaps, enhanced van Hove singularities, and Fermi surface modifications relevant for photoemission observations.

Contribution

It introduces a model of incommensurate CDW scattering based on frustrated phase separation, showing its effects on Fermi surface topology and spectral features in cuprates.

Findings

Incommensurate CDW induces local gaps in k-space.

Van Hove singularities are significantly enhanced.

Fermi surface near M-points shows suppressed spectral weight and gap formation.

Abstract

The concept of frustrated phase separation is applied to investigate its consequences for the electronic structure of the high T_c cuprates. The resulting incommensurate charge density wave (CDW) scattering is most effective in creating local gaps in k-space when the scattering vector connects states with equal energy. Starting from an open Fermi surface we find that the resulting CDW is oriented along the (10)- and (or) (01)-direction which allows for a purely one-dimensional or a two-dimensional ``eggbox type'' charge modulation. In both cases the van Hove singularities are substantially enhanced, and the spectral weight of Fermi surface states near the M-points, tends to be suppressed. Remarkably, a leading edge gap arises near these points, which, in the eggbox case, leaves finite arcs of the Fermi surface gapless. We discuss our results with repect to possible consequences for photoemission experiments.