Effects of temperature and pressure on the optical and vibrational properties of thermoelectric SnSe. Issue 17 (11th April 2019)

• Record Type: Journal Article
• Authors: Efthimiopoulos, Ilias; Berg, Matthias; Bande, Annika; Puskar, Ljiljana; Ritter, Eglof; Xu, Wei; Marcelli, Augusto; Ortolani, Michele; Harms, Martin; Müller, Jan; Speziale, Sergio; Koch-Müller, Monika; Liu, Yong; Zhao, Li-Dong; Schade, Ulrich
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 17(2019)
• Page Start: 8663
• Page End: 8678
• Publication Date: 2019-04-11
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp00897g
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes. Abstract : We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes. Our high-temperature investigations at ambient pressure have successfully reproduced the progressive enhancement of the free carrier concentration upon approaching the Pnma → Bbmm transition, whereas the pressure-induced Pnma → Bbmm transformation at ambient temperature, accompanied by an electronic semiconductor → semi-metal transition, has been identified for bulk SnSe close to 10 GPa. Modeling of the Raman-active vibrations revealed that three-phonon anharmonic processes dominate the temperature-induced mode frequency evolution. In addition, SnSe was found to exhibit a pressure-induced enhancement of the Born effective charge. Such behavior is quite unique and cannot be rationalized within the proposed effective charge trends of binary materials under pressure.