Phenomenological description of the two energy scales in underdoped superconducting cuprates

TL;DR

This paper explains the presence of two distinct energy scales in underdoped cuprate superconductors by analyzing experimental data through the YRZ model, highlighting the competition between superconductivity and pseudogap correlations.

Contribution

It demonstrates how the YRZ model accounts for the contrasting doping dependence of nodal and antinodal energy scales in underdoped cuprates.

Findings

Nodal energy scale decreases with underdoping

Antinodal energy scale increases with underdoping

Antinodal Raman intensity decreases with decreasing doping

Abstract

Raman and ARPES experiments have demonstrated that in superconducting underdoped cuprates nodal and antinodal regions are characterized by two energy scales instead of the one expected in BCS. The nodal scale decreases with underdoping while the antinodal one increases. Contrary to the behavior expected for an increasing energy scale, the antinodal Raman intensity decreases with decreasing doping. Using the Yang, Rice and Zhang (YRZ) model, we show that these features are a consequence of the non-conventional nature of the superconducting state in which superconductivity and pseudogap correlations are both present and compete for the phase space.