Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 18: Superconductivity: Poster
TT 18.7: Poster
Monday, March 18, 2024, 15:00–18:00, Poster C
Superconducting transition temperatures of V and V-Ti alloys in the presence of electronic correlations — •Dylan Jones1,2, Andreas Östlin1, Andreas Weh1, Florian Beiuseanu3, Ulrich Eckern4, Levente Vitos5, and Liviu Chioncel1,2 — 1Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, Germany — 2ACIT, University of Augsburg, Germany — 3Faculty of Science, University of Oradea, Romania — 4Institute of Physics, University of Augsburg, Germany — 5Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm, Sweden
Ordinary superconductors are widely assumed insensitive to small concentrations of nonmagnetic impurities, whereas strong disorder suppresses superconductivity, ultimately leading to a superconductor-insulator transition. In between these limiting cases, a fascinating regime may emerge where disorder enhances superconductivity. This effect is discussed here for the β-phase of V-Ti alloys. Disorder is modeled using the CPA while local electronic interactions are treated using DMFT. The McMillan formula is employed to estimate the superconducting Tc, showing a maximum at a Ti concentration of around 0.33 for a local Coulomb interaction U in the range of 2-3 eV. Our calculations quantitatively agree with the experimentally observed concentration dependent increase of Tc, and its maximal value of about 20%. We show that including local electronic correlations are a necessary extension for an improved computation of the superconducting Tc even in such simple materials like V and V-Ti alloys.
Keywords: Disorder; CPA; McMillan; transition temperature; electronic correlations