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Effect of phase transition on tungsten nitride: a first principle study
G. Subhashree, S. Sankar and R. Krithiga
Self consistent first principle calculations on superconducting material Tungsten nitride (WN) in three phases such as WC-type, NiAs-type and NaCl-type have been performed to understand their fundamental characteristics of the structural, electronic and thermal properties. The bulk modulus (B), Debye temperature (θD), density of states (N (EF)), electronic specific heat coefficient (γ), electron-phonon coupling constant (λ) and superconducting transition temperature (Tc) have been computed in terms of the electronic structure results obtained by using the tight-binding linear muffin tin orbital method based on the density functional theory (DFT) within the local density approximation (LDA). Among the considered structures, NiAs-structure is the most stable for WN compound. The bulk modulus is also found to be highest in NiAs-structure. The band structure plots and the DOS histograms confirms the metallic nature of the WN compound in three phases. The electron-phonon coupling constant is also discussed here with respect to the McMillan’s strong coupling theory.
Keywords: Phase transition, Electronic structure, Density functional theory, Tungsten nitride, Density of states, Debye temperature, Electron-phonon coupling