Localization and Interaction Effects in Strongly Underdoped La2-xSrxCuO4

TL;DR

This study investigates the magnetoresistance in underdoped La2-xSrxCuO4 films, revealing a transition from interaction effects to spin scattering dominance and suggesting superconducting fluctuations within the insulating phase.

Contribution

It provides new insights into the interplay of localization, interaction, and spin effects in strongly underdoped cuprates, highlighting the emergence of superconducting fluctuations deep inside the insulating regime.

Findings

Interaction effects dominate at high temperatures.

Spin scattering influences low-temperature behavior.

Positive orbital MR indicates superconducting fluctuations.

Abstract

The in-plane magnetoresistance (MR) in La2-xSrxCuO4 films with 0.03 < x < 0.05 has been studied in the temperature range 1.6 K to 100 K, and in magnetic fields up to 14 T, parallel and perpendicular to the CuO2 planes. The behavior of the MR is consistent with a predominant influence of interaction effects at high temperatures, switching gradually to a regime dominated by spin scattering at low T. Weak localization effects are absent. A positive orbital MR appears close to the boundary between the antiferromagnetic and the spin-glass phase, suggesting the onset of Maki-Thompson superconducting fluctuations deep inside the insulating phase.