The compounds designated as R3T4Sn13 (R = rare earth and T = transition metal) are hypothesized to be strongly correlated electron systems. Some of these compounds exhibit structural phase transitions with speculated charge-density-wave (CDW) formations. We carried out x-ray diffraction measurements in order to investigate the second-order phase transition of R3Co4Sn13 (R=La and Ce) by using single-crystalline samples synthesized by the molten Sn-flux method. Both compounds exhibit the structural superlattice transformations characterized by the wave vector q=(1/2,1/2,0) below TD≃160 K, which originate from electronic states owing to the common Co and Sn. The space group of the low-temperature phase is evidenced as a chiral cubic I213. The magnetic-susceptibility enhancement and the Co-ion valence shift below TD are signatures of a phase transition not fully attributed to the conventional CDW formation.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics