Brief Summary of research:
The research focuses on the measurement of heat flow, or thermal transport, in low-dimensional materials. Low-dimensional materials, like 2D atomic layers such as graphene, or 1D channels such as carbon nanotubes, have a wide variety of physical behaviors of fundamental interest and with promise for future applications in efficient nanoelectronics, flexible electronics, high-performance thermoelectrics, quantum sensing, and more. Thermal transport can reveal many exotic phenomena since it is sensitive to any emergent degree of freedom regardless of electrical charge. Heat is also one of the key bottlenecks for modern processor performance, leading to frequency throttling and safety issues, but measuring the electronic heat generated in nanoscale devices is a long-standing challenge.
Specific research topics related to Nanoscience and Nanotechnology:
I developed a new kind of thermal transport measurement called nonlocal noise thermometry with graphene thermometers. Using high-bandwidth microwave-frequency measurements of electronic noise, the electronic temperature of graphene can be measured. By placing multiple contacts along a specific geometry, and measuring the nonlocal noise at different pairs of terminals with a novel differential noise measurement circuit, we can measure the temperature at different locations in a multiterminal device. Using the ability of graphene to easily interface easily with many low-dimensional materials, I used this to measure electronic thermal transport properties of 2D hydrodynamic electrons, 1D electrons in carbon nanotubes, and even 0D, localized electron heat transport. Furthermore, I showed that this approach is sensitive to the heat carried in insulating materials, like spin waves in a 2D magnetic insulator, and neutral modes of a 3D spin liquid candidate material. My research depends on high-quality nanofabrication, which is crucial to the creation of these low-dimensional material-based devices. Typical processes include reactive ion etching, electron beam lithography, and thermal evaporation, as well as photolithography and sputtering.