Quantum oscillations in a d-wave vortex liquid

TL;DR

This paper presents a theoretical analysis of quantum oscillations in a d-wave vortex liquid state, reconciling experimental observations of Fermi liquid behavior with the effects of superconducting fluctuations in high magnetic fields.

Contribution

It introduces a model of a vortex-liquid state with short-range pairing correlations that explains quantum oscillations and density of states suppression in underdoped cuprates.

Findings

Quantum oscillations are consistent with a reconstructed Fermi surface.

Phase fluctuations cause a $\sqrt{H}$ suppression of the density of states.

The model reconciles Fermi liquid behavior with superconducting fluctuations.

Abstract

The observation of quantum oscillations in underdoped cuprates has generated intense debate about the nature of the field-induced resistive state and its implications for the `normal state' of high T_c superconductors. Quantum oscillations suggest an underlying Fermi liquid state at high magnetic fields H and low temperatures, in contrast with the high-temperature, zero-field pseudogap state seen in spectroscopy. Recent heat capacity measurements show quantum oscillations together with a large and singular field-dependent suppression of the electronic density of states (DOS), which suggests a resistive state that is affected by the d-wave superconducting gap. We present a theoretical analysis of the electronic excitations in a vortex-liquid state, with short range pairing correlations in space and time, that is able to reconcile these seemingly contradictory observations. We show that phase fluctuations lead to large suppression of the DOS that goes like $\sqrt{H}$ at low fields, in addition to quantum oscillations with a period determined by a Fermi surface reconstructed by a competing order parameter.