Ab initio investigation of superconductivity in orthorhombic MgPtSi

• The electronic structure of MgPtSi is studied using ab initio pseudopotential method.
• Phonons and electron–phonon interaction in MgPtSi are studied using a linear response theory.
• The acoustic phonon modes couple more strongly with electrons.
• The value of λ is found to be 0.707 which shows that MgPtSi is a conventional honon-mediated superconductor.
• The calculated Tc of 2.4 K is in excellent accordance with its experimental value of 2.5 K.

We have performed an ab initio study of electronic, vibrational and superconducting properties of the orthorhombic MgPtSi by employing the density functional theory, a linear-response formalism, and the plane-wave pseudopotential method. Our electronic results suggest that the density of states at the Fermi level is primarily contributed by Pt 5d and Si 3p states with much smaller contribution from Mg electronic states. Phonon anomalies have been found for all three acoustic branches. Due to these phonon anomalies, the acoustic branches make large contributions to the average electron-phonon coupling parameter. From the Eliashberg spectral function, the value of average electron-phonon coupling parameter is found to 0.707. Using this value, the superconducting critical temperature is obtained to be 2.4 K, in excellent accordance with its experimental value of 2.5 K.

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