The $R_5{\mathrm{Pb}}_3\mathrm{O}$ family was discovered decades ago, but has remained largely unexplored. Here, we report single-crystal growth and basic characterization for the La and Ce members of this family. At room temperature, these compounds adopt a tetragonal structure $(I4/mcm)$, where $R$ and Pb atoms form linear chains along the $c$ axis. We identify a second-order structural phase transition at 260 and 145 K for $R=$ La and Ce, respectively. Single-crystal x-ray diffraction reveals a lattice modulation below the transition temperature, resulting in $R\text{−}\mathrm{Pb}$ pairs in the $z$ direction. The broken symmetry in the low-temperature phases results in a primitive structure with space group $P4/ncc$. Transport and diffraction measurements, in agreement with density functional theory calculations, support that the $R_5{\mathrm{Pb}}_3\mathrm{O}$ $(R=\mathrm{La} \text{and} \mathrm{Ce})$ series hosts an electron-phonon coupling driven charge density wave (CDW) at low temperatures. The CDW ordering temperature is suppressed by more than 100 K by the La to Ce substitution, suggesting high-pressure sensitivity. Therefore, this family offers the potential for investigating competing orders in oxides, with heavier rare-earth members still to be explored.

Close

PrevNext

View figure in article

• Charge density waves
• Phase transitions
• Structural properties
• Oxides
• Crystal growth
• Crystallography
• Resistivity measurements
• X-ray diffraction