Magneto-optical evidence for a gapped Fermi surface in underdoped YBa2Cu3O6+x

TL;DR

This study uses magneto-optical measurements to reveal a partial gap in the Fermi surface of underdoped YBa2Cu3O6+x, supporting charge density wave models over Mott transition theories.

Contribution

It provides experimental evidence of a gapped Fermi surface in underdoped high-Tc superconductors using magneto-optical techniques.

Findings

Significant increase in Hall frequency in underdoped samples

Evidence of partial Fermi surface gapping

Results support charge density wave models

Abstract

The infrared (900-1100 cm-1) Faraday rotation and circular dichroism are measured in the normal state of underdoped High Tc superconductors and used to study the magneto-transport. YBa2Cu3O6+x thin films are investigated in the temperature range 10-300 K in magnetic fields up to 8 Tesla and as a function of oxygen concentration. A dramatic increase of the Hall frequency is observed for underdoped samples which is not consistent with the approach to a Mott transition but is consistent with a partial gapping of the Fermi surface as predicted in charge density wave models.