Upper limit on electron scattering observed
The Planckian limit is believed to be the upper boundary on scattering of charge carriers in a conducting system, and has been attributed as the origin of the linear-in-temperature resistivity observed in several 'strange metals' in recent years. In this limit, the scattering rate is predicted to depend only on fundamental constants and the temperature. A collaborative team from the Universities of Cornell, Sherbrooke, Paris-Saclay, Texas, the National High Magnetic Field Laboratory, Tallahassee and including Paul Goddard at Warwick Physics, made use of angle-dependent magnetoresistance, a technique in which electronic transport properties are monitored while rotating the sample in a large magnetic field. The team found that the results measured in a high-temperature cuprate superconductor could be readily explained with a surprisingly simple transport model including an isotropic scattering rate that is right at the predicted Planckian limit.
This work is published as "Linear-in temperature resistivity from an isotropic Planckian scattering rate" by G. Grissonnanche et al. Nature 595, 667 (2021).