MoTe2 Polymorphs: A DFT Approach to Structural, Electronic, Mechanical and Vibrational Properties

Abstract

Molybdenum ditelluride (MoTe₂), a key member of the transition metal dichalcogenides (TMDCs) family, holds significant potential for applications in electronics, energy storage, and catalysis. Despite its importance, the range of MoTe₂ structural forms that has been explored is still limited. The primary aim of this research is to identify new stable MoTe₂ polymorphs that may exist under zero-temperature and zero-pressure conditions. This study offers an in-depth analysis of 11 different structural variations (polymorphs) of MoTe₂ using advanced computational methods based on density functional theory (DFT). By employing the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional, accurate calculations of electronic properties, such as band structure, are achieved. Bonding analysis, including charge density and electron localization, reveals consistent covalent interactions across the hexagonal and trigonal forms of MoTe₂. The study also assesses the mechanical stability of these polymorphs using elastic constants, identifying both stable and metastable forms. Additionally, phonon and thermal properties, including heat capacity and entropy, are calculated for all dynamically stable polymorphs. Raman and infrared spectra provide insights into their distinct vibrational modes. These findings help distinguish structural attributes relevant to layer-specific applications. This comprehensive investigation of MoTe₂ polymorphs uncovers new stable structures and provides crucial insights for their potential use in technological applications.