Spin Fluctuation Induced Linear Magnetoresistance in Ultrathin Superconducting FeSe Films

TL;DR

This study reports a linear magnetoresistance in ultrathin FeSe/STO films near the superconducting transition, attributed to spin fluctuations, providing new insights into the interplay between magnetotransport and superconductivity.

Contribution

It introduces the first magnetotransport signature of spin fluctuations in ultrathin FeSe/STO films near the superconducting transition.

Findings

Linear magnetoresistance observed near superconducting transition.

LMR explained by magnetic field dependent disorder model.

Spin fluctuations linked to magnetotransport phenomena.

Abstract

The discovery of high-temperature superconductivity in FeSe/STO has trigged great research interest to reveal a range of exotic physical phenomena in this novel material. Here we present a temperature dependent magnetotransport measurement for ultrathin FeSe/STO films with different thickness and protection layers. Remarkably, a surprising linear magnetoresistance (LMR) is observed around the superconducting transition temperatures but absent otherwise. The experimental LMR can be reproduced by magnetotransport calculations based on a model of magnetic field dependent disorder induced by spin fluctuation. Thus, the observed LMR in coexistence with superconductivity provides the first magnetotransport signature for spin fluctuation around the superconducting transition region in ultrathin FeSe/STO films.