Orientation-Dependent Upper Critical Magnetic Field and Density of State for Uranium Ditelluride

Abstract

The superconductor UTe₂ has garnered considerable attention due to its unique spin-triplet pairing and high upper critical magnetic field, making it a promising candidate for exploring unconventional superconductivity. This study presents a theoretical investigation into the angle dependence of the upper critical magnetic field H_C2 and the temperature-dependent density of states (DOS) within UTe₂. By employing anisotropic Ginzburg–Landau theory alongside microscopic modeling, the orientation-dependent behavior of H_C2 is analyzed along key crystallographic axes, particularly the a-, b- and c-axes, which demonstrate critical fields of ≈7, 15, and 11 T respectively. These results indicate a strong anisotropy in H_C2, with a peak along the b-axis, suggesting a profound alignment effect of the spin-triplet pairs with the magnetic field. Additionally, temperature-dependent DOS calculations reveal a pronounced increase in states near the Fermi level at lower temperatures, supporting the presence of unconventional pairing with potential nodal gaps. These findings suggest a complex interplay between spin fluctuations and electronic correlations, contributing to the robust superconducting phase in UTe₂ and also provides deeper insights into the mechanisms driving superconductivity in UTe₂ and highlights its potential for applications requiring high-field superconductors.