Fermi liquid behavior of the in-plane resistivity in the pseudogap state of YBa_2Cu_4O_8

TL;DR

This study demonstrates Fermi liquid behavior in the in-plane resistivity of underdoped YBa2Cu4O8 within the pseudogap phase, revealing a quadratic temperature dependence at low temperatures consistent with a reconstructed Fermi surface.

Contribution

It provides experimental evidence of T^2 resistivity in the pseudogap state, indicating Fermi liquid behavior and suggesting a more complex Fermi surface than previously observed.

Findings

Resistivity shows T^2 dependence down to 1.5 K.

The T^2 coefficient is smaller than expected for a single Fermi pocket.

Reconstructed Fermi surface likely includes multiple pockets.

Abstract

Our knowledge of the ground state of underdoped hole-doped cuprates has evolved considerably over the last few years. There is now compelling evidence that inside the pseudogap phase, charge order breaks translational symmetry leading to a reconstructed Fermi surface made of small pockets. Quantum oscillations, [Doiron-Leyraud N, et al. (2007) Nature 447:564-568], optical conductivity [Mirzaei SI, et al. (2013) Proc Natl Acad Sci USA 110:5774-5778] and the validity of Wiedemann-Franz law [Grissonnache G, et al. (2016) Phys. Rev. B 93:064513] point to a Fermi liquid regime at low temperature in the underdoped regime. However, the observation of a quadratic temperature dependence in the electrical resistivity at low temperatures, the hallmark of a Fermi liquid regime, is still missing. Here, we report magnetoresistance measurements in the magnetic-field-induced normal state of underdoped YBa_2Cu_4O_8 which are consistent with a T^2 resistivity extending down to 1.5 K. The magnitude of the T^2 coefficient, however, is much smaller than expected for a single pocket of the mass and size observed in quantum oscillations, implying that the reconstructed Fermi surface must consist of at least one additional pocket.