Electronic structure and low-temperature study of theCe1−xLaxRh4Sn13

Abstract

Recently, it was reported that the skutterudite-related ${\mathrm{Ce}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ heavy fermion compound has a large electronic specific heat coefficient $C(T)/T$ and short-range magnetic correlations, both suggest a possible quantum critical point (QCP). We present the low-temperature specific heat, resistivity, and susceptibility of ${\mathrm{Ce}}_{1\text{\ensuremath{-}}x}{\mathrm{La}}_{x}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$, which do not confirm the presence of QCP. X-ray photoelectron spectroscopy revealed a stable configuration of Ce atoms consistent with magnetic susceptibility data. Magnetic susceptibility shows that the sixfold-degenerate multiplet of ${\mathrm{Ce}}^{3+}$ ion splits into three doublets due to the lower local symmetry of ${\mathrm{CeSn}}_{12}$ cage in the cubic ${\mathrm{Ce}}_{1\text{\ensuremath{-}}x}{\mathrm{La}}_{x}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ compounds. The resistivity, specific heat, and susceptibility data are consistent with our band-structure calculations. The chemical bondings in the unit cell of ${\mathrm{Ce}}_{1\text{\ensuremath{-}}x}{\mathrm{La}}_{x}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$, analyzed based on the difference charge density maps from band-structure calculations within the virtual crystal approximation explain the deformation of the cages and the crystal electric field properties of the system.