Fermi-liquid ground state in n-type copper-oxide superconductor Pr0.91Ce0.09LaCuO4-y

TL;DR

This study reveals that the low-doped n-type copper-oxide Pr0.91Ce0.09LaCuO4-y exhibits a Fermi-liquid ground state when superconductivity is suppressed, contrasting with p-type cuprates and previous thermal conductivity findings.

Contribution

It provides direct evidence of a Fermi-liquid ground state in n-type cuprates, challenging previous assumptions about their electronic nature.

Findings

Ground state is Fermi liquid when superconductivity is suppressed.

Contrasts with p-type cuprates with similar doping levels.

Data supports line-nodes gap model in superconducting state.

Abstract

We report nuclear magnetic resonance studies on the low-doped n-type copper-oxide Pr_{0.91}LaCe_{0.09}CuO_{4-y} (T_c=24 K) in the superconducting state and in the normal state uncovered by the application of a strong magnetic field. We find that when the superconductivity is removed, the underlying ground state is the Fermi liquid state. This result is at variance with that inferred from previous thermal conductivity measurement and contrast with that in p-type copper-oxides with a similar doping level where high-T_c superconductivity sets in within the pseudogap phase. The data in the superconducting state are consistent with the line-nodes gap model.