Angle-resolved photoemission in doped charge-transfer Mott insulators

TL;DR

This paper develops a comprehensive theory for angle-resolved photoemission spectroscopy (ARPES) in doped cuprates, incorporating realistic band structures, polaron effects, and disorder, explaining experimental features without relying on Fermi surface concepts.

Contribution

It introduces a novel theoretical framework for ARPES in charge-transfer Mott insulators that accounts for complex interactions and disorder, aligning with experimental observations.

Findings

Describes ARPES features without Fermi surface dependence.

Explains polarization and spectral shape anomalies in cuprates.

Aligns with doping-dependent properties and d-wave superconductivity.

Abstract

A theory of angle-resolved photoemission (ARPES) in doped cuprates and other charge-transfer Mott insulators is developed taking into account the realistic (LDA+U) band structure, (bi)polaron formation due to the strong electron-phonon interaction, and a random field potential. In most of these materials the first band to be doped is the oxygen band inside the Mott-Hubbard gap. We derive the coherent part of the ARPES spectra with the oxygen hole spectral function calculated in the non-crossing (ladder) approximation and with the exact spectral function of a one-dimensional hole in a random potential. Some unusual features of ARPES including the polarisation dependence and spectral shape in YBa2Cu3O7 and YBa2Cu4O8 are described without any Fermi-surface, large or small. The theory is compatible with the doping dependence of kinetic and thermodynamic properties of cuprates as well as with the d-wave symmetry of the superconducting order parameter.