Title:
Embarking on a Thermal Journey in Low Dimensions with a 21 st century thermometer: Graphene Nonlocal Noise
Abstract:
Low-dimensional materials, such as 2D monolayers, 1D nanowires, and 0D quantum dots and molecules,
are rich with many-body quantum phenomena. The reduced dimensionality, strong interactions, and
topological effects lead to new emergent degrees of freedom of fundamental interest and promise for
future applications, such as energy-efficient computation and quantum information. Thermal transport,
which is sensitive to all energy-carrying degrees of freedom and their interactions, provides a
discriminating probe to identify these emergent excitations. However, thermal measurement in low
dimensions is dominated by lattice contributions, requiring an approach to isolate the electronic thermal
conductance. In this talk, I will discuss how the measurement of nonlocal voltage fluctuations in a
multiterminal device can reveal the electronic heat transported across a mesoscopic, low-dimensional
bridge. We use 2D graphene as an electronic noise thermometer, demonstrating quantitative electronic
thermal conductance measurement over a wide temperature range in an array of dimensionalities: 2D
graphene, 1D nanotubes, 0D localized electron chains, and 3D, microscale bulk materials. I will discuss
ongoing work revealing electron hydrodynamics, interaction-mediated plasmon hopping, spin waves in a
magnetic insulator, and signs of a crossover from phonon to spin-related transport in a bulk spin liquid
candidate material.