Effect of Spin-Orbit Interaction on Physical Properties of SnAs Superconductor
Vlasenko V.A., Alien M.D.

Received: July 21, 2026

DOI: 10.31857/S0044451026120099

PDF (468.9K)

In this work, the effect of spin-orbit coupling (SOC) on the electronic structure, electron-phonon spectrum, and superconducting properties of the NaCl-type (rock-salt) compound SnAs is investigated via ab initio calculations. Inclusion of the SOC provides only a minor influence on the equilibrium lattice parameter and the electronic density of states near the Fermi level. However, it produces a notable restructuring of the high-frequency region of the electron-phonon spectrum and the Eliashberg spectral function α ²F(ω ), which in turn modifies the electron-phonon coupling constant. The calculated coupling parameter λ _el-ph equals approximately 0.59 when SOC is taken into account and 0.63 when it is neglected. The superconducting critical temperature Tc, obtained within the Migdal-Eliashberg formalism, lies in the range 3.1-4.1 K, depending on the chosen parameter of smearing for the Eliashberg function and on whether SOC is incorporated. These findings underscore the necessity of explicitly including spin-orbit coupling for a quantitatively accurate theoretical description of the superconducting state in SnAs. Keywords: superconductivity, spin-orbit coupling, electron-phonon interaction, Eliashberg spectral function