Remnant Fermi Surfaces in Photoemission

TL;DR

This paper investigates the concept of remnant Fermi surfaces in photoemission spectra of correlated electrons, revealing how they relate to true Fermi surfaces or superlattice zones depending on the system's instabilities.

Contribution

It provides a theoretical analysis of remnant Fermi surfaces across different interacting electron models, clarifying their interpretation in various physical scenarios.

Findings

Remnant Fermi surface accurately reflects the true Fermi surface in pairing systems.

In nesting systems, the remnant Fermi surface maps the superlattice Brillouin zone.

The gap in Ca₂CuO₂Cl₂ is likely caused by nesting instability.

Abstract

Recent experiments have introduced a new concept for analyzing the photoemission spectra of correlated electrons -- the remnant Fermi surface (rFs), which can be measured even in systems which lack a conventional Fermi surface. Here, we analyze the rFs in a number of interacting electron models, and find that the results fall into two classes. For systems with pairing instabilities, the rFs is an accurate replica of the true Fermi surface. In the presence of nesting instabilities, the rFs is a map of the resulting superlattice Brillouin zone. The results suggest that the gap in Ca_2CuO_2Cl_2 is of nesting origin.