Bad metallic transport in geometrically frustrated models

Numerous strongly correlated metals display non-Fermi liquid (NFL) properties over a broad range of temperatures. The intermediate-scale NFL often displays a regime of T-linear resistivity, accompanied by a finite extrapolated zero temperature entropy. In this work, we study a family of geometrically frustrated models with an interaction scale far exceeding the single-particle bandwidth. Starting from the interaction-only limit, which can be solved exactly, we study the transport and thermodynamic properties perturbatively at leading order in the single-particle bandwidth. Over a broad range of intermediate temperatures, we find evidence of "bad" metallic behavior accompanied by T-linear resistivity. At commensurate fillings, the bad-metallic regime eventually crosses over into correlated insulators in the limit of low temperatures. We discuss the relevance of our results to experiments in cold-atom and moiré heterostructure based platforms.