Inelastic phonon transport across atomically sharp metal/semiconductor interfaces
QS Li and F Liu and S Hu and HF Song and SS Yang and HL Jiang and T Wang and YK Koh and CY Zhao and FY Kang and JQ Wu and XK Gu and B Sun and XQ Wang, NATURE COMMUNICATIONS, 13, 4901 (2022).
Understanding thermal transport across metal/semiconductor interfaces is crucial for the heat dissipation of electronics. The dominant heat carriers in non-metals, phonons, are thought to transport elastically across most interfaces, except for a few extreme cases where the two materials that formed the interface are highly dissimilar with a large difference in Debye temperature. In this work, we show that even for two materials with similar Debye temperatures (Al/Si, Al/GaN), a substantial portion of phonons will transport inelastically across their interfaces at high temperatures, significantly enhancing interface thermal conductance. Moreover, we find that interface sharpness strongly affects phonon transport process. For atomically sharp interfaces, phonons are allowed to transport inelastically and interface thermal conductance linearly increases at high temperatures. With a diffuse interface, inelastic phonon transport diminishes. Our results provide new insights on phonon transport across interfaces and open up opportunities for engineering interface thermal conductance specifically for materials of relevance to microelectronics. Phonons are thought to transport elastically across most interfaces. Here, the authors show that a substantial portion of phonons transport inelastically, adding another heat conduction channel and enhancing thermal conductance across interfaces.
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