Superconductivity in monolayer Pb on Si(111) from first principles

► In this study we calculate the electron-phonon coupling for monolayer Pb on Si(111). ► The total electron-phonon coupling is found to be reduced from the bulk value and to account accurately for the observed superconducting Tc. ► The Mermin-Wagner theorem is not found to be violated, as the Pb-Si interaction removes the strict two-dimensional constraint from the Pb layer.