We develop Johnson noise thermometry applicable to mesoscopic devices with variable source impedance with high bandwidth for fast data acquisition. By implementing differential noise measurement and two-stage impedance matching, we demonstrate noise measurement in the frequency range 120-250 MHz with a wide sample resistance range 30 {\Omega}-100 k{\Omega} tuned by gate voltages and temperature. We employ high-frequency, single-ended low noise amplifiers maintained at a constant cryogenic temperature in order to maintain the desired low noise temperature. We achieve thermometer calibration with temperature precision up to 650 mK on a 10 K background with 30 s of averaging. Using this differential noise thermometry technique, we measure thermal conductivity on a bilayer graphene sample spanning the metallic and semiconducting regimes in a wide resistance range, and we compare it to the electrical conductivity.
@article{arxiv.2008.12739,
title = {High-Bandwidth, Variable-Resistance Differential Noise Thermometry},
author = {Artem Vladimirovich Talanov and Jonah Waissman and Takashi Taniguchi and Kenji Watanabe and Philip Kim},
journal= {arXiv preprint arXiv:2008.12739},
year = {2021}
}
Comments
9 pages, 4 figures; submitted to Review of Scientific Instruments