Signatures of a momentum independent pseudogap in the electronic density of states and Raman spectroscopy of the underdoped cuprates

TL;DR

This paper introduces a hybridization model for the pseudogap in underdoped cuprates, revealing a momentum-independent pseudogap that mimics d-wave features and affects electronic density of states and Raman spectra.

Contribution

It presents a novel hybridization phenomenology showing how a momentum-independent pseudogap can produce d-wave-like signatures in spectroscopic measurements.

Findings

A momentum independent pseudogap opens asymmetrically from the Fermi surface.

The pseudogap causes a suppression in the density of states with a hump feature.

Distinguishes s-wave and d-wave orderings via tunneling spectra.

Abstract

We propose a hybridization phenomenology to describe the pseudogap state of the underdoped cuprates. We show how a momentum independent pseudogap opens asymmetrically from the Fermi-surface but symmetric to the zeroes of the hybridized bonding dispersion, which results in false d-wave characteristics of the pseudogap at the Fermi level. By comparing against a d-wave form factor we illustrate the difficulty in identifying a momentum independent order in momentum averaged quantities such as the electronic Raman response. We identify a suppression in the single-particle density of states which produces a hump feature which should be observable experimentally in tunnelling $dI/dV$ spectra and distinguishes the s-wave and d-wave ordering scenarios.