Observation of 5f electrons in the itinerant limit: Three-dimensional electronic structure of UB₂

We have derived the three-dimensional band structure and Fermi surfaces of itinerant uranium compound UB₂ by soft x-ray angle-resolved photoelectron spectroscopy. We have observed clear energy dispersions and Fermi surfaces with large contribution from the U 5f states. The obtained results have been compared with the result of band-structure calculation within the local-density-functional approximation as well as the results of de Haas–van Alphen (dHvA) study. The qualitative agreement has been obtained in the size and topology of the Fermi surfaces with the band-structure calculation and the dHvA measurement. Meanwhile, their band structure near the Fermi level is slightly different from the calculation. This might be due to a dynamic renormalization beyond the local-density approximation band calculations even in the very itinerant 5f compound.