Theoretical studies of the pressure-induced phase transition and elastic properties of BeS

• Published in: Journal of alloys and compounds 2015-02, Vol.623, p.304-310
• Main Authors: Ji, Xu, Yu, Yang, Ji, Junyi, Long, Jianping, Chen, Jianjun, Liu, Daijun
• Format: Article
• Language: English
• Subjects: Band structure of solids; BeS; Elastic anisotropy; Elastic constants; Elastic properties; Electronic properties; Electronics; Energy gap; Energy gaps (solid state); First-principles; Mathematical analysis; Phase transformations; Phase transition; Pressure dependence
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.10.151

•Transition pressure from B3 to B8 of BeS is 58.86GPa.•Elastic properties of BeS under pressure are predicted for the first time.•Elastic moduli of BeS increase monotonically with increasing pressure.•Elastic anisotropy of BeS has been investigated. First-principles calculations were performed to investigate the structural, electronic and elastic properties of BeS in both B3 and B8 structures. The structural phase transition from B3 to B8 occurs at 58.86GPa with a volume decrease of 10.74%. The results of the electronic band structure show that the energy gap is indirect for B3 and B8 phases. The pressure dependence of the direct and indirect band gaps for BeS has been investigated. Especially, the elastic constants of B8 BeS under high pressure have been studied for the first time. The mechanical stability of the two phases has been discussed based on the pressure dependence of the elastic constants. In addition, the pressure dependence of bulk modulus, shear modulus, Young’s modulus, elastic wave velocities and brittle–ductile behavior of BeS are all successfully obtained. Finally, the elastic anisotropy has been investigated by using two different methods.