An investigation was made of the temperature evolution of the electronic structure using UV photo-emission spectroscopy with state-of-the-art energy resolution (1.4meV) and band structure calculations in order to probe the origin of a low-temperature anomaly in the physical properties. Comparison of experimental and theoretical results suggested that electron correlation was not significant in this system and that the electronic states in the vicinity of the Fermi level, F, were of mixed character. High-resolution spectra at various temperatures revealed a pseudo-gap <100K, which evolved gradually with a decrease in temperature.

Origin of Ground State Anomaly in LaB6 at Low Temperatures. Medicherla, V.R.R., Patil, S., Singh, R.S., Maiti, K.: Applied Physics Letters, 2007, 90[6], 062507