Abstract

Nematic quantum critical points have long been thought of as a driver of non-Fermi liquid behaviour, however, it is now known that a symmetry allowed coupling to strain restores well-defined quasiparticles below a crossover temperature. In this region, the critical behaviour is dominated by the coupling to acoustic phonons. We demonstrate however, that the elastocaloric effect deviates from this behaviour, implying that the collective modes of the fermions still display non-Fermi liquid behaviour to leading order in temperature, all the way down to the quantum critical point. We also consider an analogy to altermagnets, where a very similar coupling emerges and is linearly dependent on the magnetic field strength, allowing for a case where the crossover temperature can be tuned via an external parameter.