Elastoresistive and elastocaloric anomalies at magnetic and electronic-nematic critical points

This work identifies critical anomalies in measurements of the elastoresistivity and the elastocaloric coefficient at both the structural-nematic and antiferromagnetic phase transitions of an iron pnictide. The authors explain the magnitude and functional forms of these critical anomalies from the strain dependence of the transition temperatures. Because there is typically a strain of the trivial representation that couples to the square of any order parameter, these effects should manifest at all second order transitions. The increasing adoption of strain techniques makes this work particularly timely.