Dresden 2020 – wissenschaftliches Programm
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MA 20: PhD Focus Session: Symposium on SStrange Bedfellows – Magnetism Meets Superconductivity" (joint session MA/AKjDPG)
MA 20.9: Vortrag
Dienstag, 17. März 2020, 12:45–13:00, HSZ 04
Electronic and magnetic character of UTe2 unconventional superconductor — Alexander B. Shick1 and •Warren E. Pickett2 — 1Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic — 2Department of Physics, University of California-Davis, Davis, California, USA
The interplay between ferromagnetism and superconductivity is a challenging problem in the coupling between the two major states of condensed matter. We report density functional theory plus Hubbard U calculations for recently discovered the orthorhombic uranium dichalcogenide superconductor . The UTe2 displays superconductivity below 1.7 K, with the anomalous feature that the specific heat coefficient does not vanish at zero temperature limit, but rather weakly diverges, suggesting very low energy ungapped quantum fluctuations. The analysis of the experimental data indicates that this actinide compound is a nearly ferromagnetic spin-triplet superconductor. The DFT+U calculations for ferromagnetic alignment  reveal that the states are dominated by the j=5/2 configuration, with the jz = ± 1/2 sectors being effectively degenerate and half-filled. The Fermi surfaces are large and strongly metallic, and display low-dimensional features, reminiscent of the ferromagnetic superconductor UGe2. Our calculations can provide a platform for modeling unusual behavior of UTe2.  S. Ran et al., Science 365, 684 (2019);  A. B. Shick, and W. E. Pickett, PRB 100, 134502 (2019).