В четверг 6 ноября в 16:00 по Москве состоится семинар лаборатории LPEM, ESPCI.
Название доклада: Cartography of Thermal conductivity in 2D material, beyond standard model for out-of-plane and in-the-plane
Докладчик: Julien Chaste
Аннотация: Efficient thermal management at the nanoscale is crucial to the performance and reliability of electronic and optical devices. Among them, diamond, boron arsenide, and cubic boron nitride are promising candidates for next-generation CMOS heat spreader or thermal rectifiers, as they offer innovative solutions for thermal regulation in modern nanoelectronics. Materials with high structural anisotropy offer exciting prospects as heat spreaders, as exhibited naturally within two-dimensional (2D) materials or 2D van der Waals (vdW) heterostructures. Their structural anisotropy is reflected in their thermal transport properties. Graphene and thin graphite films are remarkably high 2D in-plane thermal conductors up to 5000 W·m^{-1}·K^{-1}, mostly due to their exceptionally long phonon mean free paths. Meanwhile, out-of-plane thermal conductivity in some engineer two-dimensional heterostructures can be as low as 0.009 W·m^{-1}·K^{-1}, which is close to perfect thermal insulation and comparable to xenon gas. Not the less, in 2D material, different intriguing phonon transport regimes that deviate from the classical Fourier law emerge at low dimensions and within specific temperature windows. An intriguing non-Fourier heat conduction regime is the hydrodynamic phonon transport. In this regime, the thermal conductivity k_{2D} is no longer an intensive property of the material. Instead, k_{2D} is defined at the local level, and depends on the sample length and width leading to a major challenge for experimental studies. Despite these advances, direct and quantitative mapping of thermal transport in 2D materials remains highly challenging. Very few studies have directly measured spatial temperature profiles along suspended samples subjected to a controlled thermal gradient. In this work, we introduce a custom-built thermal characterization platform that combines Joule-heated microheaters—providing a well-defined and tunable heat flux—with spatially-resolved Raman thermometry cartography. It thus provides a unique capability to quantitatively probe non-Fourier and hydrodynamic phonon transport in monoisotopic hBN or other 2D materials. To advance our understanding of non-classical phonon transports regimes, community must be capable of measuring local thermal conductivity with high precision.
Zoom link: https://espci.zoom.us/j/84625417218?pwd=44XzBRRjX9odPRCfAGSj5fg5faFiiI.1ID: 846 2541 7218
Passcode: J_Fourier