First-principles investigation of structural, electronic and mechanical properties of some Dysprosium chalcogenides, DyX (X = S, Se and Te)

The structural, electronic and mechanical properties of heavy rare earth (DyX, X = S, Se and Te) chalcogenide compounds, which crystallize in B(1)phase, have been investigated for the first time using FP-LAPW method within the framework of density functional theory. The local spin density approximation with Hubbard parameter (LSDA + U) has been used for exchange-correlation potentials. The calculated ground-state properties such as lattice constants, bulk moduli and pressure derivatives are in good agreement with previously reported results. Further, magnetic moments for these compounds have also been calculated. The metallic nature of these compounds was confirmed by electronic band structures and density of states. Furthermore, to meet the applications of such materials, elastic constants and mechanical properties such as Young modulus, shear modulus, Poisson ratio, anisotropic factor,B/Gratio and Cauchy's pressure have also been calculated. DyS shows brittle nature, while DySe and DyTe show ductile nature under ambient conditions.