Regular Article

Investigation on bismuth-based oxide perovskites MBiO₃ (M = Rb, Cs, Tl) for structural, electronic, mechanical and thermal properties

¹ Department of Physics, Govt. Motilal Vigyan Mahavidyalya College, Bhopal 462008, Madhya Pradesh, India
² Department of Physics, Govt. Degree College Nowshera, Jammu and Kashmir 185151, Nowshera, India
³ Department of Physics, Government Post Graduate Jahanzeb College Saidu Sharif, Swat 19130, Khyber Pakhtunkhwa, Pakistan
⁴ Department of Physics, Lovely Professional University, Phagwara 144411, India

^a e-mail: azmatupesh@gmail.com, azmat@jc.edu.pk

Received: 8 February 2020
Received in final form: 10 April 2020
Published online: 3 June 2020

Abstract

Herein, we report our density functional theory calculations for structure, electronic, thermodynamic and mechanical properties of MBiO₃ (M = Rb, Cs, Tl), compounds of perovskites oxide family. Exchange-correlation potential was treated with generalized gradient and local density approximations. From available ionic data, the tolerance factors and lattice constants were calculated. The values of tolerance factors provided the stability guarantee of MBiO₃ compounds in cubic phase while the obtained lattice constants are in accordance to the available data. The cubic phase stability was further confirmed from elastic constants. The electronic structure results disclosed these materials as metallic. Mechanically, all the three perovskites were found as brittle from Cauchy’s pressure, Pugh ratio and Poisson’s ratio. The thermodynamic calculations have been performed using quasi-harmonic Debye model. Thermal properties like Debye temperature, specific heat capacity and thermal expansion have been presented with the variation of temperature and pressure.