Phonon-mediated superconductivity in the transition metal trioxides XO3 (X=Ru,Re,Os,Ir,Pt) under pressure

A recent experiment by P. F. Shan et al. (arXiv:2304.09011) found that rhenium trioxide ${\mathrm{ReO}}_{3}$, a simple metal at ambient pressure, becomes superconducting with a transition temperature as high as 17 K at 30 GPa. In this paper, we analyze the electron-phonon origin of superconductivity in rhombohedral ${\mathrm{ReO}}_{3}$ in detail. In addition, we also conduct a high-throughput screening of isostructural transition metal trioxides $X{\mathrm{O}}_{3}$ in searching for potential pressure-induced superconductors. In total, 28 $X{\mathrm{O}}_{3}$ compounds have been studied, of which four candidates ${\mathrm{RuO}}_{3}, {\mathrm{OsO}}_{3}, {\mathrm{IrO}}_{3}$, and ${\mathrm{PtO}}_{3}$ are predicted superconducting with the transition temperatures of 26.4, 30.3, 0.9, and 2.8 K at 30 GPa, respectively. Both ${\mathrm{IrO}}_{3}$ and ${\mathrm{PtO}}_{3}$ stay superconducting even at ambient pressure. In ${\mathrm{ReO}}_{3}, {\mathrm{RuO}}_{3},{\mathrm{OsO}}_{3}$, and ${\mathrm{IrO}}_{3}$, the conduction electrons around the Fermi level are dominantly from the X-d and the O-$2p$ orbitals, and their electron-phonon coupling originates from the lattice dynamics of both the heavier transition metal atom and the oxygen atom. Inclusion of spin-orbital coupling would mildly suppress the transition temperatures of these transition metal trioxide superconductors except ${\mathrm{RuO}}_{3}$.