Abstract
The present research is a systematic computational study focused on structural, mechanical, electronic, vibrational, optical and thermo-dynamical properties of zinc-blende (B3) structured beryllium chalcogenides BeZ (Z=S, Se, Te) compounds using ATK-DFT method using PZ and PBEsol exchange and correlation potentials within the local density approximation (LDA) and the generalized gradient approximation (GGA) respectively and their comparison. The k-point and energy cut-off values were tested and provided convergence in self-consistent calculations. The structural parameters such as lattice constant, bulk modulus, second order elastic constants (C11, C12, C44) and material properties (B, G, Y and σ) for these crystals are computed and discussed. To explain the electronic properties, electronic energy band structure, complex band structures, phonon band structure, phonon density of state and electron density distribution are plotted. The effect of pressure on elastic constant, material properties and phase transitions are also studied, including phase transition from ZB structure to NiAs appearing at 53 GPa, 49 GPa and 33 GPa for BeS, BeSe, and BeTe respectively.
Highlights
The II-VI Semiconductor group material beryllium chalcogenides BeZ (Z=S, Se and Te) are promising materials and have attracted the attention of researchers due to large band gaps (2.7 eV-5.5 eV) [1] and other technological applications in electronic devices; they have remarkable physical, chemical and mechanical properties [2,3,4,5,6,7,8,9,10,11]
The exchange and correlation potentials were treated within the Local Density Approximation (LDA) of Perdew and Zunger (PZ) [36]; and generalized-gradient approximation (GGA) of Perdew Burke Ernzerhof solids (PBEsol) for the interaction of the electrons with the ion cores
In the present study, a comparative computational analysis of structural, mechanical, electronic, vibrational and thermodynamical properties of zinc-blende (B3) structured BeZ (Z=S, Se, Te) compounds is performed using Atomistix Tool Kit (ATK)-DFT method within LDA and GGA at ambient pressure
Summary
The II-VI Semiconductor group material beryllium chalcogenides BeZ (Z=S, Se and Te) are promising materials and have attracted the attention of researchers due to large band gaps (2.7 eV-5.5 eV) [1] and other technological applications in electronic devices; they have remarkable physical, chemical and mechanical properties [2,3,4,5,6,7,8,9,10,11] Extensive work on these chalcogenides has been done based on optical band gap characterization and phonon properties under various physical conditions of pressure, temperature etc. Owning a higher value of the bulk modulus, beryllium chalcogenides have high values of hardness and stability [13]
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