Disorder-induced local strain distribution in Y-substituted TmVO4

Quenched disorder induced by chemical substitution is potentially important in shaping phase diagrams of strongly correlated quantum materials. Chemical substitution results in local strain, and hence conventional theoretical approaches often treat the effects of chemical substitution as random fields. However, this assumption is not fully justified given the long-range nature of strains in solids. Here, the authors explore the disorder effect arising from chemical substitution in TmVO₄, an insulator, which undergoes ferroquadrupolar (nematic) order at low temperatures. They find quantitative evidence that the local strain fields are indeed correlated. This result implies that the effects of chemical substitution in all-electronic nematic materials need to be treated with greater degrees of sophistication than the `simple' random field Ising model.