Electronic structure of HoB4: A photoelectron spectroscopic study

We investigated the electronic structure of a rare earth tetraboride, HoB4 - a frustrated antiferromagnet, as a function of temperature using high resolution photoelectron spectroscopy. The B 1s core level spectrum exhibits multiple features corresponding to non-equivalent borons present in the compound. The high resolution valence band spectra exhibit a dip at the Fermi level that grows with the decrease in temperature manifesting the influence of disorder present in the system.