Ab initio investigation of spin orbit coupling effect on the physical properties of IrGe superconductor. (March 2019)

• Record Type: Journal Article
• Authors: Tütüncü, H.M.; Uzunok, H.Y.; Karaca, Ertuǧrul; Baǧcı, S.; Srivastava, G.P.
• Is Part Of: Intermetallics. Volume 106(2019:Mar.)
• Page Start: 107
• Page End: 114
• Publication Date: 2019-03
• Subjects: Intermetallics -- Density functional theory -- Electronic structure -- Superconducting properties -- Ab–initio calculations -- Physical properties; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2018.12.017
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: We have aimed to explore the influence of spin orbit coupling (SOC) on the electronic, elastic, mechanical, lattice dynamical and electron-phonon interaction properties of the simple orthorhombic IrGe using first principles density functional calculations within the generalized gradient approximation. The effect of SOC on the above properties of IrGe is mainly associated with Ir atom which possesses a 5d orbital and much heavier mass than that of Ge atom. The calculated values of nine independent elastic constants satisfy all the stability criteria, indicating that IrGe is mechanically stable in its MnP-type crystal structure. Also, no imaginary phonon frequencies are found in the phonon dispersion curves, indicating the dynamical stability of IrGe in its orthorhombic structure. Inclusion of SOC leads to the hardening of some low-frequency phonon modes which influences the electron-phonon interaction. Furthermore, inclusion of SOC leads to a decrease in dominant peaks of the Eliashberg function, and thus decrease in the values of the electron-phonon scattering parameter λ as well as the superconducting transition temperature T c . Using the calculated value of λ with SOC, the value of T c is obtained to be 5.09 K which compares very well with the recent measured value of 5.17 K. Highlights: Ab initio pseudopotential method is used to examine the effect of SOC on the physical properties of IrGe superconductor. The inclusion of SOC causes to the splitting of some electronic bands. Ir-related vibrations couple strongly with electrons. The inclusion of SOC decreases the value of _ from 0.953 to 0.785. The calculated TC of 5.087 with SOC consistent very well with its measured value of 5.17 K.