Theory of tunnelling into and from cuprates

TL;DR

This paper presents a theoretical model for cuprates that explains various tunnelling and photoemission spectra features, including the temperature-independent gap, asymmetry, and incoherent structures, considering bipolaron formation and realistic band effects.

Contribution

It introduces a comprehensive spectral density model for cuprates that accounts for bipolaron effects, disorder, and thermal fluctuations, explaining experimental spectral features.

Findings

Reproduces temperature-independent gap in spectra

Explains asymmetry in emission and injection

Accounts for dip-hump features at high energies

Abstract

A single-particle spectral density is proposed for cuprates taking into account the bipolaron formation, realistic band structure, thermal fluctuations and disorder. Tunnelling and photoemission (PES) spectra are described, including the temperature independent gap observed both in the superconducting and normal states, the emission/injection asymmetry, the finite zero-bias conductance, the spectral shape in the gap region and its temperature and doping dependence, dip-hump incoherent asymmetric features at high voltage (tunnelling) and large binding energy (PES).