The quasiskutterudite superconductor La3Co4Sn13 undergoes a phase transition at T∗=152 K. By measuring the temperature dependence of heat capacity, electrical resistivity, and the superlattice reflection intensity using x rays, we explore the character of the phase transition at T∗. Our lattice dynamic calculations found imaginary phonon frequencies around the M point when the high-temperature structure is used in the calculations, indicating that the structure is unstable at the zero-temperature limit. The combined experimental and computational results establish that T∗ is associated with a second-order structural transition with q=(0.5,0.5,0) (or the M point). Further electronic band structure calculations reveal Fermi surface sheets with low-curvature segments, which allow us to draw qualitative comparison with both Sr3Ir4Sn13 and Sr3Rh4Sn13 in which similar physics has been discussed recently.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics