کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8203215 | 1530511 | 2018 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Soft-phonon dynamics of the thermoelectric β-SnSe at high temperatures
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک و نجوم (عمومی)
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چکیده انگلیسی
Results of inelastic neutron scattering experiments on SnSe single crystals at high temperatures along with theoretical studies based on the density functional theory are reported. Our experiments reveal significant softening of the transverse acoustic branch along the [0,ξ,0] direction in the low-temperature α-SnSe of Pbnm symmetry as temperature approaches Tc=807 K from below. This process is followed by a condensation of the zone-boundary Y-phonon of the high-temperature β-SnSe with Cmcm symmetry at the onset of phase transition. The employed theoretical approach supports experimental observations and demonstrates that the phase change in SnSe is mediated by an unstable zone-boundary phonon with the Y2+ irreducible representation within the Cmcm symmetry space group of the high-temperature β-SnSe. The present work provides a detailed understanding of the soft-mode dynamics in SnSe and conclusively shows that the αâβ structural transformation in this currently topical thermoelectric material is of displacive type.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics Letters A - Volume 382, Issue 29, 26 July 2018, Pages 1937-1941
Journal: Physics Letters A - Volume 382, Issue 29, 26 July 2018, Pages 1937-1941
نویسندگان
Tapan Chatterji, Urszula D. Wdowik, Grzegorz JagÅo, Stéphane Rols, Frank R. Wagner,