Structural transition and possible pressure-induced superconductivity in a suboxide La 5 Pb 3 O
Here, in this study, we report a structural phase transition and its interplay with superconductivity in the suboxide La 5 Pb 3 O. Upon cooling through 𝑇 𝑡 = 225K, La 5 Pb 3 O transforms from a high-temperature 𝐼4/mcm to a low-temperature 𝑃4/ncc structure in which La-Pb dimerization along the 𝑐 axis occurs. This transition is accompanied by anomalies in the temperature dependence of electrical resistivity and specific heat. High-pressure electrical transport measurements reveal that hydrostatic pressure suppresses the structural transition and possibly induces superconductivity with a maximum superconducting temperature of 10 K. Density functional theory calculations show minimal changes in the electronic density of states and no gap opening at 𝐸 𝐹 across 𝑇 𝑡 , suggesting that the transition is driven by bonding effects rather than Fermi surface instability. These findings establish La 5 Pb 3 O as a promising platform for exploring the interplay between weak structural transitions and superconductivity.