Stranger than metals

In traditional metals, the temperature (T) dependence of electrical resistivity vanishes at low or high T, albeit for different reasons. Here, we review a class of materials, known as strange metals, that can violate both of these principles. In strange metals, the change in slope of the resistivity as the mean free path drops below the lattice constant, or as T -> 0, can be imperceptible, suggesting continuity between the charge carriers at low and high T. We focus on transport and spectroscopic data on candidate strange metals in an effort to isolate and identify a unifying physical principle. Special attention is paid to quantum criticality, Planckian dissipation, Mottness, and whether a new gauge principle is needed to account for the nonlocal transport seen in these materials.

Automated summary

Strange metals are a class of materials that defy the traditional temperature dependence of electrical resistivity at both low and high temperatures. By studying the transport and spectroscopic data of these materials, we aim to identify a unifying physical principle, with special focus on quantum criticality, Planckian dissipation, Mottness, and the possible requirement of a new gauge principle to explain the nonlocal transport observed in these materials.