Thermal Transport and Thermodynamic Properties of Graphene at Very Low Temperatures

California Institute Of Technology, Pasadena CA

Investigators

Abstract

***Technical Abstract**** This project explores the low temperature thermodynamic properties of graphene from 10mK to 10K. The focus is on measurements of the relevant thermal conductance channels, electron diffusion, phonon emission, and photon emission; this research will produce sensitive measurements of the electronic heat capacity. The work will be accomplished through the development of wide-bandwidth noise thermometry utilizing very sensitive, nearly quantum-limited microwave detection systems allowing to explore the difference between graphene on various substrates (SiO2, BN, etc.) and suspended flakes. Another important goal is the potential use of graphene as an ultra-sensitive bolometer and calorimeter. The initial estimates suggest that this material and measurement system will be capable of detecting single microwave photons and the photon shot noise; these capabilities would produce many opportunities in the fields of quantum measurement and quantum information. This project will be essential to the training of one junior scientist (Phd student or postdoc) and will involve summer undergraduate students. The PI will also reach out to the Navajo Nation to seek the involvement of an undergraduate student. ****Non-Technical Abstract**** Graphene is a single atomic layer of crystalline carbon, i.e. one layer of graphite from your pencil. Since 2004 when it was discovered how to easily isolate this material, there has been an intense effort to probe the remarkable electrical, mechanical, and thermal properties. In this work, measurements are made to find how heat is transported in the material and to determine the heat capacity of a tiny flake. It also explores the use of a tiny micron-sized flake of graphene as a very sensitive bolometer. A bolometer is a sensor which converts energy in the form of light or microwaves, into heat, and then this heating is detected. Bolometers have been used to provide very sensitive probes of the radiation from the big bang and future astronomy missions will require even more sensitive bolometers. From estimates, it appears that graphene can be used to create this next generation bolometer, and this study will determine if this is indeed true. These experiments will be lead by a junior scientist (Phd student of postdoc) and will also involve summer undergraduate students. The group will reach out to the Navajo Nation to seek the involvement of an undergraduate student.