Yuma Hizume | Search arXiv

arXiv2020

Effect of spin fluctuations on superconductivity in V and Nb: a first-principles study

We study the superconductivity in typical $d$-band elemental superconductors V and Nb with the recently developed non-empirical computational scheme based on the density functional theory for superconductors. The effect of ferromagnetic fluctuation (paramagnon) on the superconducting transition temperature ($T_{\rm c}$), which in principle suppress the $s$-wave superconducting pairing, is quantified without any empirical parameter. We show that the strong paramagnon effect cancels the $T_{\rm c}$-enhancing effects of the phonon-mediated pairing and dynamical screened Coulomb interaction.

cond-mat.supr-con↗

arXiv2020

Benchmark of density functional theory for superconductors in elemental materials

Systematic benchmark calculations for elemental bulks are presented to validate the accuracy of density functional theory for superconductors. We developed a method to treat the spin-orbit interaction (SOI) together with the spin fluctuation (SF) and examine their effect on the superconducting transition temperature. We found the following results from the benchmark calculations: (1) The calculations, including SOI and SF, reproduce the experimental superconducting transition temperature ($T_c$) quantitatively. (2) The effect by SOI is small excepting a few elements such as Pb, Tl, and Re. (3) SF reduces $T_c$s, especially for the transition metals, while this reduction is too weak to reproduce the $T_c$s of Zn and Cd. (4) We reproduced the absence of superconductivity for alkaline (earth) and noble metals. These calculations confirm that our method can be applied to a wide range of materials and implies a direction for the further improvement of the methodology.

cond-mat.supr-con↗