Probing the electronic structure of UTe 2 with ARPES and high-energy spectroscopy

UTe 2 has emerged as one of the most intensively studied strongly correlated materials in recent years owing to its unconventional superconductivity and the possible realization of a spin-triplet, topologically nontrivial pairing state. A central open issue concerns the nature of the U,5f electrons and their participation in low-energy quasiparticle states. In this review, we summarize recent spectroscopic studies of UTe 2 using momentum-resolved angle-resolved photoemission spectroscopy (ARPES) and element- and configuration-sensitive X-ray probes, including X-ray absorption spectroscopy (XAS), X-ray absorption near-edge structure (XANES), X-ray magnetic circular dichroism (XMCD), resonant X-ray emission spectroscopy (RXES), and resonant inelastic X-ray scattering (RIXS). A key finding is the pronounced technique dependence of the inferred electronic structure. We synthesize the present spectroscopic picture by integrating these results with modern electronic-structure calculations such as density functional theory plus dynamical mean-field theory (DFT+DMFT). These findings support an intermediate-valence ground state with significant admixture of 5f squared and 5f cubed configurations in UTe 2, and they delineate key experimental and theoretical benchmarks needed to connect the normal-state electronic structure to the superconducting mechanism.