The curious case of the structural phase transition in SnSe insights from neutron total scattering.

Autor: Jiang B; Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.; Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA., Neu J; National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA.; Dept. of Physics 77 Chieftain Way, Florida State University, Tallahassee, FL, 32306-4350, USA.; Dept. of Chemistry & Biochemistry 95 Chieftain Way 118 DLC, Florida State University, Tallahassee, FL, 32306-4390, USA.; Oak Ridge National Laboratory, Nuclear Nonproliferation Division, Oak Ridge, TN, 37831, USA., Olds D; Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.; National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973-5000, USA., Kimber SAJ; Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université Bourgogne Franche-Comté, 9 avenue Alain Savary, BP 47870, F-21078, Dijon Cedex, France., Page K; Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA. kpage10@utk.edu.; Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA. kpage10@utk.edu., Siegrist T; National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA. tsiegrist@fsu.edu.; Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310-6046, USA. tsiegrist@fsu.edu.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2023 Jun 03; Vol. 14 (1), pp. 3211. Date of Electronic Publication: 2023 Jun 03.
DOI: 10.1038/s41467-023-38454-0
Abstrakt: At elevated temperatures SnSe is reported to undergo a structural transition from the low symmetry orthorhombic GeS-type to a higher symmetry orthorhombic TlI-type. Although increasing symmetry should likewise increase lattice thermal conductivity, many experiments on single crystals and polycrystalline materials indicate that this is not the case. Here we present temperature dependent analysis of time-of-flight (TOF) neutron total scattering data in combination with theoretical modeling to probe the local to long-range evolution of the structure. We report that while SnSe is well characterized on average within the high symmetry space group above the transition, over length scales of a few unit cells SnSe remains better characterized in the low symmetry GeS-type space group. Our finding from robust modeling provides further insight into the curious case of a dynamic order-disorder phase transition in SnSe, a model consistent with the soft-phonon picture of the high thermoelectric power above the phase transition.
(© 2023. The Author(s).)
Databáze: MEDLINE
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