Effect of mesoscopic inhomogeneities on local tunnelling density of states

TL;DR

This paper presents a theoretical study on how mesoscopic inhomogeneities and charge modulations influence the local tunnelling density of states in superconducting cuprates, explaining experimental STM observations.

Contribution

It introduces a model incorporating mesoscopic disorder and charge modulations to better reproduce experimental LDOS features in cuprates.

Findings

Mesoscopic disorder leads to point-like spectroscopic features.

Stripe-like charge modulations are crucial for matching experimental spectra.

Impurity scattering potential's momentum dependence affects LDOS patterns.

Abstract

We carry out a theoretical analysis of the momentum dependence of the Fourier-transformed local density of states (LDOS) in the superconducting cuprates within a model considering the interference of quasiparticles scattering on quenched impurities. The impurities introduce an external scattering potential, which is either nearly local in space or it can acquire a substantial momentum dependence due to a possible strong momentum dependence of the electronic screening near a charge modulation instability. The key new effect that we introduce is an additional mesoscopic disorder aiming to reproduce the inhomogeneities experimentally observed in scanning tunnelling microscopy. The crucial effect of this mesoscopic disorder is to give rise to point-like spectroscopic features, to be contrasted with the curve-like shape of the spectra previously calculated within the interfering-quasiparticle schemes. It is also found that stripe-like charge modulations play a relevant role to correctly reproduce all the spectral features of the experiments.