Open Access

Density Functional Theory Analysis of the Electronic Properties of the Ge₂Sb₂Te₅

S. N. Garibova^1,2, M. E. Aliyev³, U. I. Ashurova⁴, L. C. Suleymanova⁴, A. M. Kerimova¹, S. A. Rzayeva¹, S. O. Guseynova¹, H. I. Novruzova¹, R. Z. Amirov¹, F. Sarcan⁵

1 Institute of Physics, Ministry of Science and Education of the Republic of Azerbaijan, Baku, 1073, Azerbaijan
2 Department of Physics and Electronics, Khazar University, Baku, 1096, Azerbaijan
3 Department of Electrical Engineering, Faculty of Engineering-Architecture, Nakhchivan State University, Nakhchivan, 7012, Azerbaijan
4 Department of Energy, Faculty of Engineering, Mingachevir State University, Mingachevir, 4500, Azerbaijan
5 Department of Physics, Faculty of Science, Istanbul University, Vezneciler, Istanbul, 34134, Turkey

* Corresponding Author: S. N. Garibova. Email:

Chalcogenide Letters 2025, 22(12), 999-1008. https://doi.org/10.15251/CL.2025.2212.999

Accepted 05 September 2025; Issue published 03 December 2025

Abstract

In this work, the electronic behavior of the chalcogenide semiconductor Ge₂Sb₂Te₅ was examined using a first-principles computational approach. The study was carried out within the density functional theory framework, where the spin-polarized generalized gradient approximation was applied through the Atomistix ToolKit software. A double-zeta polarized basis set formed the foundation of the calculations, while exchange–correlation interactions were treated using the Perdew–Burke–Ernzerhof functional. Sampling of the Brillouin zone was performed according to the Monkhorst–Pack method with a 2 × 2 × 2 k-point grid, ensuring accuracy through special-point integration. Atomic configuration optimization, also conducted in Atomistix ToolKit, allowed the determination of the most energetically favorable arrangement for the Ge–Sb–Te lattice. Structural characteristics—including crystallite size and crystallinity—were evaluated using the Debye–Scherrer and Halder–Wagner analytical method. The relaxation of the unit cell revealed a marked redistribution of atoms, most notably between Ge and Te positions, resulting in higher symmetry and improved stability. Furthermore, the analysis indicated that distinct Ge–Sb–Te phases exhibit measurable differences in lattice constants, which in turn influence their physical performance. The refined structural model, characterized by enhanced symmetry and stability, provides a reliable representation of crystalline Ge₂Sb₂Te₅, making it a valuable reference for phase-change memory technology development.

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