Fermi liquid behaviour in an underdoped high Tc superconductor

TL;DR

This study demonstrates that underdoped high Tc superconductor YBa2Cu3O6+x exhibits Fermi liquid behavior in its quasiparticle excitations, despite being near a Mott insulating state, through magnetic quantum oscillation measurements.

Contribution

It provides experimental evidence that quasiparticles in an underdoped high Tc superconductor obey Fermi-Dirac statistics, supporting Fermi liquid theory in this regime.

Findings

Quasiparticle excitations follow Fermi-Dirac distribution

Fermi liquid behavior persists despite proximity to Mott insulator

Quantum oscillations reveal Fermi surface properties

Abstract

We use magnetic quantum oscillations in the underdoped high Tc superconductor YBa_2Cu_3O_(6+x) (x=0.56) measured over a broad range of temperatures 100 mK<T<18 K to extract the form of the distribution function describing the low-lying quasiparticle excitations in high magnetic fields. Despite the proximity of YBa_2Cu_3O_(6+x) (x=0.56) to a Mott insulating state, various broken symmetry ground states and/or states with different quasiparticle statistics, we find that our experimental results can be understood in terms of quasiparticle excitations obeying Fermi-Dirac statistics as in the Landau Fermi liquid theory.