Periodic Anderson model for magnetism and superconductivity in UTe2
Abstract
We provide and analyze a periodic Anderson model for studying magnetism and superconductivity in UTe2, a recently-discovered candidate for a topological spin-triplet superconductor. The 24-band tight-binding model reproduces the band structure obtained from a DFT+U calculation consistent with an angle-resolved photoemission spectroscopy. The Coulomb interaction of f-electrons enhances Ising ferromagnetic fluctuation along the a-axis and stabilizes spin-triplet superconductivity of either B3u or Au symmetry. When effects of pressure are taken into account in hopping integrals, the magnetic fluctuation changes to antiferromagnetic one, and accordingly spin-singlet superconductivity of Ag symmetry is stabilized. Based on the results, we propose pressure-temperature and magnetic field-temperature phase diagrams revealing multiple superconducting phases as well as an antiferromagnetic phase. In particular, a mixed-parity superconducting state with spontaneous inversion symmetry breaking is predicted.