Incoherent mid-infrared charge excitation and the high energy anomaly in the photoemission spectra of cuprates

TL;DR

This paper proposes that the high energy anomaly in cuprate photoemission spectra results from interaction with an overdamped mid-infrared bosonic mode, linking it to incoherent charge responses in high-Tc materials.

Contribution

It introduces a semi-phenomenological model connecting the high energy anomaly to overdamped bosonic modes and incoherent charge responses, explaining spectral features in cuprates.

Findings

High energy anomaly caused by overdamped bosonic mode.

Connection between optical conductivity and incoherent charge response.

Damping explains 'waterfall' dispersion and spectral linewidths.

Abstract

On the basis of a semi-phenomenological model, it is argued that the high energy anomaly observed in recent photoemission experiments on cuprates is caused by interaction with an overdamped bosonic mode in the mid-infrared region of the spectrum. Analysis of optical conductivity allows to connect this excitation to the incoherent charge response reported for the majority of high Tc materials and some other perovskites. We show that its large damping is an essential feature responsible for the "waterfall" dispersion and linewidth of the spectral weight.