First-principles calculation of electronic structure and mechanical properties of hexagonal GaM(M=S/Se/Te)
Simulations of electronic structure and elasto-mechanical properties of GaM(M=S/Se/Te)with lay-ered hexagonal P63/mmc structure are investigated based on density-functional theory(DFT).The optimized lattice of P63/mmc-GaM(M=S/Se/Te)matches the experimental results.The bandgap values obtained using the HSE06 generalization are closer to the experimental values than those obtained by PBE.The single-crystal elastic constants of P63/mmc-GaM(M=S/Se/Te)obtained by both strain-energy-strain(E-S)and stress-strain(S-S)methods meet the elasto-mechanical stability criterion.A subsequent analysis of the mechanical properties such as polycrystalline elastic modulus of the three materials is carried out based on the stress-strain(S-S)method,which is closer to the literature values.Poisson's ratio and B/G values indicate that P63/mmc-GaM(M=S/Se/Te)shows brittleness.Three-dimensional stereograms of the anisotropy factor,elastic modulus E,shear modulus G,and linear compression coefficient β show the degree of elastic anisotropy of the material,re-spectively.At zero temperature and pressure,the first transverse sound velocity of P63/mmc-GaM(M=S/Se/Te)is the largest in the[100]direction,and the two transverse waves TA1 and TA2 are the slowest in the[001]direction.
density function theoryhexagonal P63/mmc-GaM(M=S/Se/Te)electronic structuremechanical propertiesanisotropy
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