The filled skutterudite CeOs${}_4$As${}_{12}$: a hybridization gap semiconductor

Abstract

X-ray diffraction, electrical resistivity, magnetization, specific heat, and thermoelectric power measurements are presented for single crystals of the new filled skutterudite compound {\CeOsAs}, which reveal phenomena that are associated with f - electron - conduction electron hybridization. Valence fluctuations or Kondo behavior dominates the physics down to $T$ $\sim$ 135 K. The correlated electron behavior is manifested at low temperatures as a hybridization gap insulating state. The small energy gap $\Delta$${}_1$/k${}_B$ $\sim$ 73 K, taken from fits to electrical resistivity data, correlates with the evolution of a weakly magnetic or nonmagnetic ground state, which is evident in the magnetization data below a coherence temperature $T$${}_{coh}$ $\sim$ 45 K. Additionally, the low temperature electronic specific heat coefficient is small, $\gamma$ $\sim$ 19 mJ/mol K${}^2$. Some results for the nonmagnetic analogue compound {\LaOsAs} are also presented for comparison purposes.

Submitted to the Proceedings of the National Academy of Sciences of the United States of America

References in corpus (2)

• On the thermoelectricity of correlated electrons in the zero-temperature limit
• Transport properties in CeOs${}_4$Sb${}_{12}$: Possibility of the ground state being semiconducting