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.
@article{arxiv.0912.3022,
title = {Fermi liquid behaviour in an underdoped high Tc superconductor},
author = {Suchitra E. Sebastian and N. Harrison and M. M. Altarawneh and Ruixing Liang and D. A. Bonn and W. N. Hardy and G. G. Lonzarich},
journal= {arXiv preprint arXiv:0912.3022},
year = {2011}
}