Optomechanical Measurement of Thermal Transport in Two-Dimensional MoSe₂ Lattices

Abstract

Nanomechanical resonators have emerged as sensors with exceptional sensitivities. These sensing capabilities open new possibilities in the studies of the thermodynamic properties in condensed matter. Here, we use mechanical sensing as a novel approach to measure the thermal properties of low-dimensional materials. We measure the temperature dependence of both the thermal conductivity and the specific heat capacity of a transition metal dichalcogenide (TMD) monolayer down to cryogenic temperature, something that has not been achieved thus far with a single nanoscale object. These measurements show how heat is transported by phonons in two-dimensional systems. Both the thermal conductivity and the specific heat capacity measurements are consistent with predictions based on first-principles.

Dynamically-enhanced strain in atomically thin resonators

“… 1 and, at the same time, to record the micro-Raman scattering response of the atomically thin membrane. We have chosen electrostatic rather than photothermal actuation 39 to attain large RMS amplitudes while at the same time avoiding heating and photothermal backaction effects 10 , 11 , possibly leading to additional damping 8 , self-oscillations 10 , mechanical instabilities and sample damage. All measurements were performed at room temperature under high vacuum (see “Methods” section and Supplementary Notes 1 to 8 ).…”

“…Since the first demonstration of mechanical resonators made from suspended graphene layers 1 , considerable progress has been made to conceive nano-mechanical systems based on 2D materials 2 , 3 with well-characterised performances 4 – 8 , for applications in mass and force sensing 9 but also for studies of heat transport 10 , 11 , non-linear mode coupling 12 – 14 and optomechanical interactions 5 , 15 , 16 . These efforts triggered the study of 2D resonators beyond graphene, made for instance from transition metal dichalcogenide layers 8 , 11 , 17 , 18 and van der Waals heterostructures 19 – 21 . In suspended atomically thin membranes, a moderate out-of-plane stress gives rise to large and swiftly tunable strains, in excess of 1% 22 , 23 , opening numerous possibilities for strain-engineering 24 .…”

Interlayer Exciton–Polaron in Atomically Thin Semiconductors

“…The bilayers with large values of L can be designed similarly to the drum-like structures of refs. [25,26].…”

“…We assume that there is no material sandwiched between the layers, similarly to the structures studied in refs. [25,26].…”

Role of Optical Phonons in Bulk Molybdenum Diselenide Thermal Properties Probed by Advanced Raman Spectroscopy

“…b) Temperature-dependent change in in-plane and out-of-plane thermal conductivities of MoSe 2 from previous works. [14,15,[43][44][45]…”