Effect of the behavior on direct–indirect electronic transitions of SrZrO3 nanowires grown in the crystallographic directions [100] and [110]: Ab-initio study

Abstract

In the present work, we studied a set of strontium zirconate nanowires of different diameters oriented in the directions [100] and [110]. The density functional theory calculations were performed using the quantum espresso code, which confidently employs a combination of plane waves. In this study, we utilized a pseudopotential proposed by Perdew, Burke, and Ernzerhof to model the exchange–correlation energy using a generalized gradient approximation. In the study’s first phase, we performed a structural optimization of the nanowires by adjusting the atomic positions and lattice parameters. After calculating the electronic band structure and density of states, we found that the strontium zirconate nanowires in this study are semiconductors. The nanowires in the [100] direction have an indirect transition, while those in the [110] direction have a direct transition. Besides, the bandgap varies with diameter. We also calculated the density of states projected. Based on the results, it can be observed that the p orbital of oxygen is the primary contributor to the density of states in the valence region. On the other hand, in the conduction region, the density of states is mainly affected by the d and s orbitals of zirconium. Due to their exceptional electronic properties, strontium zirconate nanowires are up-and-coming candidates for photocatalysis and solar cell applications.