Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 11: Electronic Structure Theory
O 11.1: Vortrag
Montag, 5. September 2022, 15:00–15:15, H6
Quantum Nuclear Effects in Thermal Transport of Semiconductors and Insulators — •Hagen-Henrik Kowalski1, Matthias Scheffler1, Mariana Rossi2, and Christian Carbogno1 — 1The NOMAD Laboratory at the FHI-MPG and HU, Berlin, Germany — 2MPI for Structure and Dynamics of Matter, Hamburg, Germany
Accounting for the nuclear motion is essential for the prediction of various material properties, from thermal conductivity to the relative stability of different polymorphs. Often, it is assumed that quantum nuclear effects (QNEs) are decisive at low temperatures, but that anharmonic effects can be neglected in this limit. Conversely, it is often presumed that anharmonicity is influential at elevated temperatures, but that QNEs are not active in this limit. In this work, we investigate the interplay of QNEs and anharmonicity by extending a recently proposed anharmonicity metric [1] to path integral molecular dynamics (PIMD). Our ab initio MD and PIMD calculations for solid Argon, Silicon, Lithium Hydrid, and Pentacene further substantiate that QNEs can have a massive impact even at room temperature and beyond, especially in weakly bonded systems [2]. Furthermore, we show that QNEs can induce strong anharmonic effects –beyond the applicability realm of perturbation theory– even at 0K. We discuss the underlying microscopic mechanisms and hence elucidate why QNEs and strong anharmonicity often go hand in hand in real materials.
[1] F. Knoop, et.al., Phys. Rev. Mat. 4, 083809, (2020).
[2] M.Rossi, J. Chem. Phys. 154, 170902 (2021)