Brian Skinner (Ohio State University)

Date: Mon. November 4th, 2024, 12:45 pm-1:45 pm
Location: Foldy Room (Rockefeller 221)
Website: https://sites.google.com/view/skinner-physics

Title: Johnson noise thermometry using ohmic and hydrodynamic electrons

Brian Skinner

Department of Physics, the Ohio State University

Abstract:

Current through a resistor exhibits temperature-dependent white noise fluctuations called Johnson-Nyquist noise. For a 2D electron system, measuring the magnitude of these fluctuations provides a direct measurement of the electron temperature and enables methods for inferring specific heat and thermal conductivity. Here I show how to understand Johnson noise both for electrons whose flow is dictated by Ohm’s law and for electrons whose flow is hydrodynamic. I then discuss experimental results from the group of Philip Kim, which use Johnson noise measurements to demonstrate a novel method for inferring specific heat and thermal conductivity for arbitrary materials and quasiparticle excitations. Experiments in the Corbino geometry also reveal a novel, qualitative signature of hydrodynamic flow without the need for nonlocal measurements.

 

Bio:

Brian Skinner is an associate professor of theoretical condensed matter physics at Ohio State University. He did his PhD with Boris Shklovskii at the University of Minnesota, followed by postdoctoral positions at Argonne National Lab and at MIT. He has been on the faculty at OSU since 2020. Brian has broad interests in physics, including topological materials, 2D electron physics, the statistical mechanics of quantum entanglement, and the intersection between condensed matter physics and game theory.

Host: Shulei Zhang