Theoretical investigation of the superconductivity mechanism of BaIr2As2

Highlights: • The structural and electronic properties of BaIr₂As₂ are theoretically investigated. • Phonons and electron–phonon interaction in BaIr₂As₂ are studied using a linear response theory. • Acoustic and low-frequency optical phonon modes couple more strongly with electrons. • Calculations for λ suggest that all phonon modes couple strongly with electrons. • The calculated T_c value of 2.337 K is comparable with its experimental value of 2.450 K. -- Abstract: Based on first-principles pseudopotential plane-wave method within the generalised gradient approximation, I have studied the structural, electronic, vibrational and BCS superconducting properties of BaIr₂As₂. The calculated electronic structure and density of states suggest that the bonding is a combination of covalent, ionic and metallic in nature and that the Fermi level falls in one of the peaks in the electronic density of states. The electron–phonon interaction calculations suggest that the mechanism for superconductivity is heavily governed by interactions of electrons with acoustic phonon modes and low-frequency optical phonon modes. By integrating the Eliashberg spectral function, the value of average electron–phonon coupling parameter is found to be 0.64 and the superconducting critical temperature is calculated to be 2.337 K, in excellent agreement with the experimentally reported value of 2.450 K.