Determining the underlying Fermi surface of strongly correlated superconductors

TL;DR

This paper reviews methods for determining the Fermi surface in strongly correlated superconductors, highlighting inaccuracies caused by pseudogap effects and emphasizing the need for strong coupling theories in ARPES analysis.

Contribution

It critically examines existing FS determination methods in high-temperature superconductors and underscores the importance of strong coupling theories for accurate characterization.

Findings

Standard methods often yield erroneous FS results near half filling.

Pseudogap effects significantly distort FS measurements at low temperatures.

Strong coupling theories are essential for correct FS interpretation in ARPES experiments.

Abstract

The notion of a Fermi surface (FS) is one of the most ingenious concepts developed by solid state physicists during the past century. It plays a central role in our understanding of interacting electron systems. Extraordinary efforts have been undertaken, both by experiment and by theory, to reveal the FS of the high temperature superconductors (HTSC), the most prominent strongly correlated superconductors. Here, we discuss some of the prevalent methods used to determine the FS and show that they lead generally to erroneous results close to half filling and at low temperatures, due to the large superconducting gap (pseudogap) below (above) the superconducting transition temperature. Our findings provide a perspective on the interplay between strong correlations and superconductivity and highlight the importance of strong coupling theories for the characterization as well as the determination of the underlying FS in ARPES experiments.