Linear nonsaturating magnetoresistance in kagome superconductor CsV3Sb5 thin flakes

TL;DR

This study reports the observation of linear nonsaturating magnetoresistance in ultrathin kagome superconductor CsV3Sb5, revealing dimensional and temperature-dependent crossovers linked to charge density wave fluctuations.

Contribution

It demonstrates the dimensional and temperature crossover of LMR in CsV3Sb5 thin flakes and suggests 2D CDW fluctuations as a possible origin, offering new insights into kagome superconductor physics.

Findings

LMR observed in CsV3Sb5 thin flakes

Crossover from LMR to quadratic B MR above CDW T

Crossover from LMR to sublinear MR at ~20 nm thickness

Abstract

Linear nonsaturating magnetoresistance (LMR) represents a class of anomalous resistivity response to external magnetic field that has been observed in a variety of materials including but not limited to topological semi-metals, high-Tc superconductors and materials with charge/spin density wave (CDW/SDW) orders. Here we report the observation of LMR in layered kagome superconductor and CDW material CsV3Sb5 thin flakes, as well as the dimensional crossover and temperature (T) crossover of such LMR. Specifically, in ultrathin CsV3Sb5 crystals, the magnetoresistance (MR) exhibits a crossover from LMR at low T to quadratic B dependence above the CDW transition temperature; the MR also exhibits a crossover from LMR to sublinear MR for sample thickness at around ~20 nm at low T. We discuss several possible origins of the LMR and attribute the effect to two-dimensional (2D) CDW fluctuations. Our results may provide a new perspective for understanding the interactions between competing orders in kagome superconductors.