  Realization of tunable superconductivity with concomitant nontrivial band
topology is conceptually intriguing and highly desirable for superconducting
devices and topological quantum computation. Based on first-principles
calculations, here we present the first prediction of simultaneously tunable
superconducting transition temperature (Tc) and band topology in a
superconducting IrTe2 overlayer on a ferroelectric In2Se3 monolayer. We first
demonstrate that the Tc is substantially enhanced from that of IrTe2 nanoflakes
(Tc ~3 K) due to significant charge repartitioning around the Fermi level. More
importantly, the Tc is shown to sensitively depend on the In2Se3 polarization,
with the higher Tc of ~(8-10) K attributed to enhanced interlayer
electron-phonon coupling when the polarization is downward. The band topology
is also switched from trivial to nontrivial as the polarization is reversed
from upward to downward. These findings provide physically realistic platforms
for simultaneously tuning superconductivity and band topology in
two-dimensional heterobilayers and related heterostructures using a reversible
and nonvolatile approach.
