Universal theory of strange metals from spatially random interactions.

Abstract

Strange metals-ubiquitous in correlated quantum materials-transport electrical charge at low temperatures but not by the individual electronic quasiparticle excitations, which carry charge in ordinary metals. In this work, we consider two-dimensional metals of fermions coupled to quantum critical scalars, the latter representing order parameters or fractionalized particles. We show that at low temperatures (<i>T</i>), such metals generically exhibit strange metal behavior with a <i>T</i>-linear resistivity arising from spatially random fluctuations in the fermion-scalar Yukawa couplings about a nonzero spatial average. We also find a <i>T</i> ln(1/<i>T</i>) specific heat and a rationale for the Planckian bound on the transport scattering time. These results are in agreement with observations and are obtained in the large <i>N</i> expansion of an ensemble of critical metals with <i>N</i> fermion flavors.