Volume contraction in CeB4induced by delocalized Ce4felectrons

Abstract

We have investigated the delocalized nature of Ce 4$f$ electrons in CeB${}_{4}$, employing the first-principles total energy electronic structure calculations. We have shown that CeB${}_{4}$ has a paramagnetic ground state in agreement with experiment, and that the valence state of Ce is rather close to trivalent (${f}^{1}$), but far from tetravalent (${f}^{0}$). The anomalous lattice constant of CeB${}_{4}$, which strongly deviates from the Lanthanides contraction curve, is well explained by the delocalized nature of Ce $4f$ electrons. We have also examined the charge densities and the Fermi surfaces of CeB${}_{4}$, based on density functional theory band structure calculations.