Measurement of the $B_{1g}$ and $B_{2g}$ components of the elastoresistivity tensor for tetragonal materials via transverse resistivity configurations

TL;DR

This paper introduces a new transverse elastoresistance measurement technique to directly determine strain-induced resistivity anisotropy in tetragonal materials, demonstrated on BaFe₂As₂, offering a complementary approach to existing methods.

Contribution

The paper presents a novel transverse elastoresistance measurement method that simplifies and directly measures elastoresistivity components in tetragonal materials.

Findings

Successfully measured the $2m_{xy,xy}$ elastoresistivity coefficient in BaFe₂As₂.

Demonstrated the effectiveness of the transverse technique compared to traditional methods.

Provided new insights into the nematic susceptibility of tetragonal materials.

Abstract

The elastoresistivity tensor $m_{ij,kl}$ relates changes in resistivity to strains experienced by a material. As a fourth-rank tensor, it contains considerably more information about the material than the simpler (second-rank) resistivity tensor; in particular, for a tetragonal material, the $B_{1g}$ and $B_{2g}$ components of the elastoresistivity tensor ($m_{xx,xx}-m_{xx,yy}$ and $2m_{xy,xy}$, respectively) can be related to its nematic susceptibility. Previous experimental probes of this quantity have focused exclusively on differential longitudinal elastoresistance measurements, which determine the induced resistivity anisotropy arising from anisotropic in-plane strain based on the difference of two longitudinal resistivity measurements. Here we describe a complementary technique based on \textit{transverse} elastoresistance measurements. This new approach is advantageous because it directly determines the strain-induced resistivity anisotropy from a single transverse measurement. To demonstrate the efficacy of this new experimental protocol, we present transverse elastoresistance measurements of the $2m_{xy,xy}$ elastoresistivity coefficient of BaFe$_2$As$_2$, a representative iron-pnictide that has previously been characterized via differential longitudinal elastoresistance measurements.