Regular article Putting DFT to the trial: First principles pressure dependent analysis on optical properties of cubic perovskite SrZrO 3 Ghazanfar Nazir a, b, * , Afaq Ahmad b , Muhammad Farooq Khan a , Saad Tariq b a Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747, South Korea b Centre of Excellence in Solid State Physics, University of the Punjab, Lahore, Pakistan article info Article history: Received 8 July 2015 Received in revised form 21 July 2015 Accepted 27 July 2015 Available online 31 July 2015 Keywords: First principle Cubic phase SrZrO 3 High pressure phase Density functional theory Optical properties Perovskite abstract Here we report optical properties for cubic phase Strontium Zirconate (SrZrO 3 ) at different pressure values (0, 40, 100, 250 and 350) GPa under density functional theory (DFT) using Perdew-Becke-Johnson (PBE-GGA) as exchange-correlation functional. In this article we first time report all the optical properties for SrZrO 3 . The real and imaginary dielectric functions has investigated along with reflectivity, energy loss function, optical absorption coefficient, optical conductivity, refractive index and extinction coeffi- cient under hydrostatic pressure. We demonstrated the indirect and direct bandgap behavior of SrZrO 3 at (0) GPa and (40, 100, 250 and 350) GPa respectively. In addition, static dielectric constant, Optical bandgap, Plasma frequency and Static refractive index has also been reported. We verified the Penn's model and showed the inverse relation between static dielectric constant and optical bandgap. Further, we proved the direct relation between static dielectric constant and static refractive index. Both these constants increased by increasing the pressure. Our investigation explored that the material preserve its positive value of refractive index at all pressure values and thus is not a negative index metamaterial. Also, we measured Plasma frequency for SrZrO 3 which also increase by increasing the pressure which leads to a conclusion that material is going to be destabilize. © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction In recent days, researchers are busy in finding materials that have potential uses like hydrogen sensors, fuel cells and data storage devices such as random access memory, high intensity violet-blue light emission, optical wave-guides, high temperature oxygen sensors and capacitors in different functional devices [1e6]. Perovskite having general formula ABO 3 are very fundamental materials to be used in various functional devices. These materials due to their wonderful properties of ferroelectricity and piezo- electricity have great attraction for the researchers to investigate them with provoking details. In the recent period, the focus of experimental research is the zirconate perovskite. A very few theoretical approach has been done on these perovskite. Among zirconate perovskite, strontium zirconate (SrZrO 3 ) is very inter- esting material because of its high temperature protonic conduc- tivity [7]. Besides this, SrZrO 3 also has great potential for high voltage and high capacitor reliability applications. High dielectric constant, large value of breakdown strength and low leakage cur- rent are some of its fundamental characteristics [8,9]. Kennedy et al. used powder neutron diffraction and Rietveld method to investigate the phase transitions in SrZrO 3 [10]. These people gave the solid evidence for the pathway of SrZrO 3 and said this material is first orthorhombic (Pnma) changes to orthorhombic (Cmcm) at about 970 K, then changes to tetragonal (14/mcm) at about 1100 K and then finally to cubic (Pm3m) at about 1400 K. It was also suggested that these materials have very high melting temperature of about 2920 K [11]. First principle method is used to study structural, electronic, optical and magnetic properties of materials [12e15]. Mete's group of researchers reported high temperature electronic properties of cubic phase SrZrO 3 [16]. Terki et al. used full-potential linearized augmented plane wave (FP- LAPW) method to investigate the structural, electronic and optical properties of BaTiO 3 and SrZrO 3 [17]. Evarestov et al. studied the density functional theory (DFT) LCAO and plane wave (PW) calcu- lations for the known four phases of SrZrO 3 [18,19]. It has been observed that previous studies on SrZrO 3 mainly focused on its structural and electrical properties using experi- mental approach but few researchers also reported its optical * Corresponding author. E-mail address: zafarforall2004@gmail.com (G. Nazir). Contents lists available at ScienceDirect Computational Condensed Matter journal homepage: http://ees.elsevier.com/cocom/default.asp http://dx.doi.org/10.1016/j.cocom.2015.07.002 2352-2143/© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Computational Condensed Matter 4 (2015) 32e39