The Hubbard model description of the photoemission TCNQ singular features

TL;DR

This paper applies the pseudofermion dynamical theory to the 1D Hubbard model, revealing power-law singular spectral features that match photoemission data in TTF-TCNQ, and details their momentum, energy, and weight distributions.

Contribution

It introduces a comprehensive analysis of spectral features in the 1D Hubbard model using PDT, connecting theoretical lines to experimental TCNQ peaks.

Findings

Power-law singular spectral features are identified across the (k, ω)-plane.

Charge and spin branch lines correspond to observed TCNQ photoemission peaks.

Spectral weight distribution is governed by pseudofermion phase shifts.

Abstract

In this paper we use the pseudofermion dynamical theory (PDT) in the study of the one-electron removal singular spectral features the one-dimensional Hubbard model. The PDT reveals that in the whole $(k, \omega)$-plane such features are of power-law type and correspond to well defined lines of three types: the charge singular branch lines, the spin singular branch lines, and the border lines. One of our goals is the study of the momentum and energy dependence of the spectral-weight distribution in the vicinity of such lines. We find that the charge and spin branch lines correspond to the main tetracyanoquinodimethane (TCNQ) peak dispersions observed by angle-resolved photoelectron spectroscopy in the quasi-1D organic conductor tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ). Our expressions refer to all values of the electronic density and on-site repulsion $U$. The weight distribution in the vicinity of the singular spectral lines is fully controlled by the overall pseudofermion phase shifts. Moreover, the shape of these lines is determined by the bare-momentum dependence of the pseudofermion energy dispersions.