Superconductivity at lower doping in monolayer 1T-NbSe2

Determine whether, upon reducing the electron doping from the overdoped regime reported for monolayer 1T-NbSe2 in a 1T/1H-NbSe2 heterostructure, the system exhibits a superconducting phase.

Background

The paper demonstrates that monolayer 1T-NbSe2, when placed on a monolayer 1H-NbSe2 substrate, becomes electron doped via charge transfer and realizes a doped Mott insulating phase on the triangular Star-of-David charge-density-wave superlattice. Spectroscopy and statistical analysis reveal both half-filled and fully filled sites, as well as non-local charge correlations inconsistent with purely random disorder, indicating underlying many-body interactions.

In their concluding discussion, the authors assess the phase diagram context and judge the investigated heterostructure to lie in an overdoped regime. They explicitly pose the open question of whether superconductivity would emerge at lower doping levels, highlighting a key unresolved issue for future experimental and theoretical exploration of correlated phases in this monolayer platform.