Skelton, JM;
Burton, LA;
Parker, SC;
Walsh, A;
Kim, C-E;
Soon, A;
Buckeridge, J;
... Tanaka, I; + view all
(2016)
Anharmonicity in the High-Temperature Cmcm Phase of SnSe: Soft Modes and Three-Phonon Interactions.
Physical Review Letters
, 117
(7)
, Article 075502. 10.1103/PhysRevLett.117.075502.
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Abstract
The layered semiconductor SnSe is one of the highest-performing thermoelectric materials known. We demonstrate, through a first-principles lattice-dynamics study, that the high-temperature Cmcm phase is a dynamic average over lower-symmetry minima separated by very small energetic barriers. Compared to the low-temperature Pnma phase, the Cmcm phase displays a phonon softening and enhanced three-phonon scattering, leading to an anharmonic damping of the low-frequency modes and hence the thermal transport. We develop a renormalization scheme to quantify the effect of the soft modes on the calculated properties, and confirm that the anharmonicity is an inherent feature of the Cmcm phase. These results suggest a design concept for thermal insulators and thermoelectric materials, based on displacive instabilities, and highlight the power of lattice dynamics calculations for materials characterization.
Type: | Article |
---|---|
Title: | Anharmonicity in the High-Temperature Cmcm Phase of SnSe: Soft Modes and Three-Phonon Interactions |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1103/PhysRevLett.117.075502 |
Publisher version: | http://dx.doi.org/10.1103/PhysRevLett.117.075502 |
Language: | English |
Additional information: | Published by the American Physical Society. This article is available under the terms of the Creative Commons Attribution 3.0 License. |
Keywords: | Science & Technology, Physical Sciences, Physics, Multidisciplinary, Physics, Performance Bulk Thermoelectrics, Augmented-wave Method, Lead Chalcogenides, Pbte |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
URI: | https://discovery.ucl.ac.uk/id/eprint/1513272 |
1. | United States | 6 |
2. | China | 4 |
3. | France | 1 |
4. | Russian Federation | 1 |
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