Observation of a possible charge-density-wave transition in cubic Ce3Co4Sn13

Abstract

We report an observation of a first-order phase transition in Ce${}_{3}$Co${}_{4}$Sn${}_{13}$ by means of the specific heat, electrical resistivity, Seebeck coefficient, and thermal conductivity, as well as ${}^{59}$Co nuclear magnetic resonance (NMR) measurements. The phase transition has been evidenced by marked features near ${T}_{\mathrm{o}}\ensuremath{\simeq}155$ K in all measured physical quantities except for magnetic susceptibility. This excludes a magnetic origin for the observed phase transition. In addition, x-ray diffraction results below and above ${T}_{\mathrm{o}}$ confirm the absence of a structural change, suggesting that the peculiar phase transition is possibly related to an electronic origin and/or electron-lattice coupling such as the formation of a charge density wave (CDW). As a matter of fact, the disappearance of the double-peak feature of ${}^{59}$Co NMR central lines below $T$${}_{\text{o}}$ can be realized as the spatial modulation of the electric field gradient due to incommensurate CDW superlattices. Also, a distinct peak found in the spin-lattice relaxation rate near $T$${}_{\text{o}}$ manifests a phase transition and its feature can be accounted for by the thermally driven normal modes of the CDW. From the NMR analyses, we obtained a consistent picture that the change of electronic structures below $T$${}_{\text{o}}$ is mainly due to the weakening of $p$-$d$ hybridization. Such an effect could result in possible electron-lattice instability and, thus, the formation of a CDW state in Ce${}_{3}$Co${}_{4}$Sn${}_{13}$.