Phonon Lifetimes throughout the Brillouin Zone at Elevated Temperatures from Experiment and AbInitio.

Albert Glensk,Jürgen Neuhaus,Winfried Petry,Jörg Neugebauer,Blazej Grabowski,Klaudia Hradil,Tilmann Hickel,Michael Leitner

doi:10.1103/physrevlett.123.235501

Abstract

We obtain phonon lifetimes in aluminium by inelastic neutron scattering experiments, by abinitio molecular dynamics, and by perturbation theory. At elevated temperatures significant discrepancies are found between experiment and perturbation theory, which disappear when using molecular dynamics due to the inclusion of full anharmonicity and the correct treatment of the multiphonon background. We show that multiple-site interactions are small and that local pairwise anharmonicity dominates phonon-phonon interactions, which permits an efficient computation of phonon lifetimes.

Highlights

We obtain phonon lifetimes in aluminium by inelastic neutron scattering experiments, by ab initio molecular dynamics, and by perturbation theory
At elevated temperatures significant discrepancies are found between experiment and perturbation theory, which disappear when using molecular dynamics due to the inclusion of full anharmonicity and the correct treatment of the multiphonon background
Phonon lifetimes have been successfully calculated at room temperature from the third-order force constant tensors employing perturbation theory (PT) [4,5,6,7,8,9] and recently extended to higher orders [10]

Summary

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Albert Glensk ,1,2,* Blazej Grabowski ,3 Tilmann Hickel ,1 Jörg Neugebauer ,1 Jürgen Neuhaus ,4 Klaudia Hradil ,4,† Winfried Petry ,4 and Michael Leitner 4,‡. We obtain phonon lifetimes in aluminium by inelastic neutron scattering experiments, by ab initio molecular dynamics, and by perturbation theory. At elevated temperatures significant discrepancies are found between experiment and perturbation theory, which disappear when using molecular dynamics due to the inclusion of full anharmonicity and the correct treatment of the multiphonon background. In this Letter we report fully q-dependent phonon linewidths in Al by means of inelastic neutron scattering up to the melting point. We show that a quantitative agreement between experiment and theory at elevated temperatures can only be achieved from molecular dynamics since it probes (i) the full anharmonicity and (ii) naturally occurring contributions due to multiphonon background scattering.

Neutron counts

DFT PT

DC F