标题： 通过横向电阻配置测量四角材料的弹性电阻张量的$B_{1g}$和$B_{2g}$分量 显示英文标题

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

摘要： 弹性电阻率张量$m_{ij,kl}$将电阻率的变化与材料所经历的应变相关联。 作为四阶张量，它比更简单的（二阶）电阻率张量包含更多关于材料的信息；特别是，对于四方材料，弹性电阻率张量的$B_{1g}$和$B_{2g}$分量（分别对应$m_{xx,xx}-m_{xx,yy}$和$2m_{xy,xy}$）可以与其向列态敏感度相关联。 以往对此量的实验探测主要集中在微分纵向弹性电阻测量上，这些测量通过两次纵向电阻率测量的差异来确定由于平面内各向异性应变引起的电阻率各向异性。 在此我们描述一种基于\textit{横向的}弹性电阻测量的互补技术。 这种方法的优势在于它可以通过一次横向测量直接确定应变引起的电阻率各向异性。 为了证明这种新实验协议的有效性，我们展示了BaFe$_2$As$_2$的横向弹性电阻率系数$2m_{xy,xy}$的横向弹性电阻测量结果，这是一种之前已通过微分纵向弹性电阻测量方法进行表征的代表性铁砷化物。 显示英文摘要

摘要： 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.