Ultra-sensitive and Wide Bandwidth Thermal Measurements of Graphene at Low Temperatures

摘要: Graphene is a material with remarkable electronic properties and exceptional thermal transport near room temperature, which have been well examined understood. However at very low temperatures the thermodynamic are much less explored somewhat surprisingly, expected to exhibit extreme isolation. Here we demonstrate an ultra-sensitive, wide-bandwidth measurement scheme probe of electron gas graphene. We employ Johnson noise thermometry microwave frequency sensitively measure temperature resolution $4 mK/\sqrt{Hz}$ bandwidth 80 MHz. measured electron-phonon coupling from 2-30 K charge density $2\cdot 10^{11} cm^{-2}$. Utilizing bolometric mixing, sensed oscillations period 430 ps determined heat capacity be 10^{-21} J/(K\cdot \mu m^2)$ 5 consistent that two dimensional, Dirac gas. These measurements suggest graphene-based devices together wide can generate substantial advances in areas ultra-sensitive bolometry, calorimetry, terahertz photo-detection, mixing for applications such as observational astronomy quantum information measurement.