Quantum Matter Seminar

Linear temperature dependence of transport coefficients in metals is habitually associated with non-Fermi-liquid physics. This talk will establish this behavior for 2D electron fluids, systems in which electron collisions assist conduction and lead to resistance decreasing with temperature. Electron fluids with simple Fermi surfaces are found to obey nonclassical hydrodynamics described by the Fermi surface shape evolving in space and time. This amoeba-like dynamics, which replaces the conventional hydrodynamics described by a velocity field, features a large family of long-lived excitations manifest as multiple viscous modes. Being unique to 2D Fermi systems, they result in a linear T dependence that extends down to lowest temperatures, as well as a Kolmogorov-like fractional power law -5/3 scaling of conductivity vs. wavenumber. These dependences provide a smoking gun for nonclassical hydrodynamics and are expected to be generic for strongly-correlated systems with near-circular Fermi surfaces. In support of these ideas, conductance linearly growing with T was recently measured in several types of 2D electron fluids.