First-Principle Calculations of Structural, Electronic, Elastic, and Optical Properties of XBaCl3 (X = In, Tl) Chloro-Perovskites

Abstract

​To investigate the potential of barium-based halide perovskites for optoelectronic applications, we performed first-principles density functional theory calculations on XBaCl₃ (X = In, Tl). These calculations were performed using the WIEN2k package, which provides detailed insights into the materials' characteristics. The code provides a silent insight into materials' characteristics and potential improvements. We employed the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) approximation to study the optimized structure, electronic, elastic, and optical properties of XBaCl3 chloro-perovskite compounds. To assess the structural stability, we are applying the Birch–Murnaghan fitting curves, confirming that each compound is structurally stable in its optimal or ground states. The IRelast Package is utilized for evaluating the elastic properties, revealing that the materials are anisotropic, brittle, and mechanically stable. In the analysis of electronic structure, the density of states and band structure were examined. It was discovered that the compounds have an indirect bandgap of 4.9 eV for InBaCl₃ and 5.6 eV for TlBaCl₃. Examining the total and partial density of states allowed us to trace how individual atomic orbitals shape the overall band structure. Furthermore, we also studied the optical response that comprises the dielectric function, refractive index, absorption coefficient, and reflectivity across an energy range of 0–13.5 eV. The materials are transparent to low-energy photons, absorbing light and exhibiting optical conductivity only in the ultraviolet range. This provides critical insight for developing more efficient and functional high-tech electronics and motivating further experimental investigation.

Received: 1 February 2026 | Revised: 28 May 2026 | Accepted: 9 July 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study

Author Contribution Statement

Shujaat Ali Khan: Conceptualization, Methodology, Software, Validation, Investigation, Writing – original draft, Writing – review & editing, Visualization. Nasir Rahman: Software, Validation, Resources, Writing – original draft, Writing – review & editing, Supervision. Shah Zeb Ullah: Conceptualization, Writing – original draft, Writing – review & editing, Visualization. Muhammad Sajjad: Validation, Resources, Supervision, Project administration. Junaid Rehman: Validation, Formal analysis, Writing – review & editing, Visualization.