Experimental detection of topological electronic state and large linear magnetoresistance in $SrSn_{4}$ superconductor

TL;DR

This study confirms the topological electronic state in SrSn4 superconductor, revealing large linear magnetoresistance and nontrivial Berry phase, indicating potential for topological superconductivity and novel electronic properties.

Contribution

First experimental evidence of topological electronic state and large magnetoresistance in SrSn4 superconductor, combining magnetotransport and quantum oscillation analyses.

Findings

Nontrivial π Berry phase detected

Large linear transverse magnetoresistance over 1200% at 5 K

Anisotropic four-fold symmetric magnetoresistance

Abstract

While recent experiments confirm the existence of hundreds of topological electronic materials, only a few exhibit the coexistence of superconductivity and a topological electronic state. These compounds attract significant attention in forefront research because of the potential for the existence of topological superconductivity, paving the way for future technological advancements. $SrSn_{4}$ is known for exhibiting unusual superconductivity below the transition temperature ($T_{C}$) of 4.8 K. Recent theory predicts a topological electronic state in this compound, which is yet to be confirmed by experiments. Systematic and detailed studies of the magnetotransport properties of $SrSn_{4}$ and its Fermi surface characterizations are also absent. For the first time, a quantum oscillation study reveals a nontrivial $\pi$ Berry phase, very light effective mass, and high quantum mobility of charge carriers in $SrSn_{4}$. Magnetotransport experiment unveils large linear transverse magnetoresistance (TMR) of more than 1200% at 5 K and 14 T. Angle-dependent transport experiments detect anisotropic and four-fold symmetric TMR, with the maximum value ($\sim$ 2000%) occurring when the angle between the magnetic field and the crystallographic b-axis is 45 degree. Our results suggest that $SrSn_{4}$ is the first topological material with superconductivity above the boiling point of helium that displays such high magnetoresistance.