Non-Fermi-Liquid Transport Phenomena in Infinite-Layer Nickelates

TL;DR

This paper investigates the non-Fermi-liquid transport phenomena in infinite-layer nickelates, revealing that spin fluctuations cause T-linear resistivity and a negative Seebeck coefficient, indicating quasi-two-dimensional electron behavior similar to certain heavy fermion systems.

Contribution

The study provides a theoretical analysis of resistivity in NdNiO$_2$, demonstrating the origin of non-Fermi-liquid behavior due to spin fluctuations within a three-dimensional tight-binding model.

Findings

T-linear resistivity from spin fluctuations

Negative T-linear Seebeck coefficient

NdNiO$_2$ exhibits quasi-two-dimensional electron behavior

Abstract

Recently discovered superconducting infinite-layer nickelates $R$NiO$_2$ ($R$=Nd, La, Pr) attract increasing attention due to their similarities to cuprates. Both $R$NiO$_2$ and YBCO cuprates exhibit the non-Fermi-liquid transport behavior, characterized by resistivity proportional to temperature near the quantum critical point of the charge or spin density wave. In this study, we analyze the resistivity of infinite-layer nickelate Nd$_{0.85}$Sr$_{0.15}$NiO$_2$ based on a three-dimensional tight-binding model within the framework of the quasi-particle picture by applying linear response theory. We take account of the self-energy by the fluctuation-exchange approximation for the Ni orbital and the T-matrix approximation for an impurity effect on the Nd orbitals. We find that (i) the $T$-linear resistivity at low temperatures is derived from the spin fluctuations, and (ii) a negative and $T$-linear Seebeck coefficient is obtained. Therefore, NdNiO$_2$ behaves as a quasi-two-dimensional electron system, similar to CeCoIn$_5$.