Experimental and Theoretical Studies on alfa-In2Se3 at High Pressure

Abstract

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/acs.inorgchem.8b00778 ; [EN] alpha(R)-In2Se3 has been experimentally and theoretically studied under compression at room temperature by means of X-ray diffraction and Raman scattering measurements as well as by ab initio total-energy and lattice-dynamics calculations. Our study has confirmed the alpha (R3m) -> beta' (C2/m) ? beta (R (3) over barm) sequence of pressure-induced phase transitions and has allowed us to understand the mechanism of the monoclinic C2/m to rhombohedral R (3) over barm phase transition. The monoclinic C2/m phase enhances its symmetry gradually until a complete transformation to the rhombohedral R (3) over barm structure is attained above 10-12 GPa. The second-order character of this transition is the reason for the discordance in previous measurements. The comparison of Raman measurements and lattice-dynamics calculations has allowed us to tentatively assign most of the Raman-active modes of the three phases. The comparison of experimental results and simulations has helped to distinguish between the different phases of In2Se3 and resolve current controversies. ; The authors acknowledge financial support from Spanish government MINECO, the Spanish Agencia Estatal de Investigacion (AEI), and Fondo Europeo de Desarrollo Regional (FEDER) under Grants No. MAT2016-75586-C4-1/2/3-P and MAT2015-71070-REDC. ; Vilaplana Cerda, RI.; Gallego-Parra, S.; Jorge-Montero, A.; Rodríguez-Hernández, P.; Muñoz, A.; Errandonea, D.; Segura, A. (2018). Experimental and Theoretical Studies on alfa-In2Se3 at High Pressure. Inorganic Chemistry. 57:8241-8252. https://doi.org/10.1021/acs.inorgchem.8b00778 ; S ; 8241 ; 8252 ; 57