Origin of ground state anomaly in LaB₆ at low temperatures

Abstract

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 (1.4 meV) 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, ε_F, possess mixed character. High resolution spectra at different temperatures T reveal a pseudogap for T<100 K, which evolves gradually with the decrease in temperature.