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Structural, vibrational and electronic properties of alpha'-Ga2S3 under compression
- Source :
- RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia, instname, Digital.CSIC. Repositorio Institucional del CSIC
- Publication Year :
- 2021
- Publisher :
- The Royal Society of Chemistry, 2021.
-
Abstract
- We report a joint experimental and theoretical study of the low-pressure phase of α′-Ga2S3 under compression. Theoretical ab initio calculations have been compared to X-ray diffraction and Raman scattering measurements under high pressure carried out up to 17.5 and 16.1 GPa, respectively. In addition, we report Raman scattering measurements of α′-Ga2S3 at high temperature that have allowed us to study its anharmonic properties. To understand better the compression of this compound, we have evaluated the topological properties of the electron density, the electron localization function, and the electronic properties as a function of pressure. As a result, we shed light on the role of the Ga–S bonds, the van der Waals interactions inside the channels of the crystalline structure, and the single and double lone electron pairs of the sulphur atoms in the anisotropic compression of α′-Ga2S3. We found that the structural channels are responsible for the anisotropic properties of α′-Ga2S3 and the A′(6) phonon, known as the breathing mode and associated with these channels, exhibits the highest anharmonic behaviour. Finally, we report calculations of the electronic band structure of α′-Ga2S3 at different pressures and find a nonlinear pressure behaviour of the direct band gap and a pressure-induced direct-to-indirect band gap crossover that is similar to the behaviour previously reported in other ordered-vacancy compounds, including β-Ga2Se3. The importance of the single and, more specially, the double lone electron pairs of sulphur in the pressure dependence of the topmost valence band of α′-Ga2S3 is stressed.<br />The authors thank the financial support from the Spanish Research Agency (AEI) under projects MALTA Consolider Team network (RED2018-102612-T) and projects MAT2016-75586-C4-2/3-P, FIS2017-83295-P, PID2019-106383GB-42/43, and PGC2018-097520-A-100, as well as from Generalitat Valenciana under Project PROMETEO/2018/123 (EFIMAT). A. M. and P. R.-H. acknowledge computing time provided by Red Espa?ola de Supercomputaci?n (RES) and MALTA-Cluster and E. L. D. S. acknowledges Marie Sklodowska-Curie Grant No. 785789-COMEX from the European Union's Horizon 2020 research and innovation program. J. A. S. also wants to thank the Ramon y Cajal fellowship (RYC-2015-17482) for financial support. We also thank the ALBA synchrotron light source for funded experiment 2017022088 at the MSPD-BL04 beamline.
- Subjects :
- Raman scattering
Electron density
Materials science
Band gap
General Physics and Astronomy
Electrons
02 engineering and technology
010402 general chemistry
Ga2S3
01 natural sciences
Molecular physics
Topology
Vibrational properties
symbols.namesake
Van der Waals forces
Ab initio quantum chemistry methods
Physical and Theoretical Chemistry
Electronic band structure
Structural properties
Gallium compounds
021001 nanoscience & nanotechnology
Electron localization function
0104 chemical sciences
Energy gap
X-ray diffraction
High pressure
Electronic properties
FISICA APLICADA
symbols
Anisotropy
Direct and indirect band gaps
van der Waals force
0210 nano-technology
Sulfur
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia, instname, Digital.CSIC. Repositorio Institucional del CSIC
- Accession number :
- edsair.doi.dedup.....e5bfc86d4bc370b2308ec73ddc6979af