The authors investigate the temperature evolution of the electronic structure of LaB6, a widely used material as high brightness cathode, using UV photoemission spectroscopy with state-of-the-art energy resolution (1.4meV) and band structure calculations in order to probe the origin of low temperature anomaly in its physical properties. Comparison of experimental and theoretical results suggests that electron correlation is not significant in this system and that the electronic states in the vicinity of the Fermi level, ϵF, possess mixed character. High resolution spectra at different temperatures T reveal a pseudogap for T<100K, which evolves gradually with the decrease in temperature.

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