Demystifying strange metal and violation of Luttinger theorem in a doped Mott insulator

Abstract

Metallic states coined strange metal (SM), with robust linear-$T$ resistivity, have been widely observed in many quantum materials under strong electron correlation, ranging from high-$T_{c}$ cuprate superconductor, organic superconductor to twisted multilayer graphene and MoTe$_{2}$/WSe$_{2}$ superlattice. Despite decades of intensive studies, the mystery of strange metal still defies any sensible theoretical explanation and has been the key puzzle in modern condensed matter physics. Here, we solve a doped Mott insulator model, which unambiguously exhibits SM phenomena accompanied with quantum critical scaling in observables, e.g. resistivity, susceptibility and specific heat. Closer look at SM reveals the breakdown of Landau's Fermi liquid without any symmetry-breaking, i.e. the violation of Luttinger theorem. Examining electron's self-energy extracted from numerical simulation provides the explanation on the origin of linear-$T$ resistivity and suggests that the long-overlooked static fluctuations in literature play an essential role in non-Fermi liquid behaviors in correlated electron systems.