Anomaly in temperature-dependent electronic structures of heavy fermion compound CeB₆

The temperature-dependent electronic structures of heavy fermion compound CeB₆ were investigated thoroughly by means of the combination of density functional theory and single-site dynamical mean-field theory. The band structure, density of states, and 4f valence state fluctuation of CeB₆ were calculated in a broad temperature range of 10 ∼ 120 K. Overall, the 4f electrons remain incoherent, approximately irrespective of environment temperature. However, we find that these observables exhibit some unusual features near 20 K. In addition, the evolutions of 4f orbital occupancy, total angular momentum, and total energy with respect to temperature show apparent non-monotonic behaviors around 20 K. The possible explanations for these tantalizing characteristics are discussed concisely.