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arXiv · 2403.13202

Superconducting transition temperatures of pure vanadium and vanadium-titanium alloys in the presence of dynamical electronic correlations

D. Jones·A. Östlin·A. Weh·F. Beiuseanu·U. Eckern·L. Vitos·L. Chioncel
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Abstract

Ordinary superconductors are widely assumed insensitive to small concentrations of random nonmagnetic impurities, whereas strong disorder suppresses superconductivity, ultimately leading to a superconductor-insulator transition. In between these limiting cases, a most fascinating regime may emerge where disorder enhances superconductivity. This effect is discussed here for the $\beta$-phase of vanadium-titanium alloys. Disorder is modeled using the coherent potential approximation while local electronic interactions are treated using dynamical mean-field theory. The McMillan formula is employed to estimate the superconducting transition temperature, showing a maximum at a Ti concentration of around $0.33$ for a local Coulomb interaction $U$ in the range of $2$ to $3$ eV. Our calculations quantitatively agree with the experimentally observed concentration dependent increase of $T_c$, and its maximal value of about $20\%$.

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D. Jones, A. Östlin, A. Weh, F. Beiuseanu, U. Eckern, L. Vitos, L. Chioncel. 2024-03-19. Superconducting transition temperatures of pure vanadium and vanadium-titanium alloys in the presence of dynamical electronic correlations. https://doi.org/10.1103/physrevb.109.165107

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