In this study, we propose and investigate novel Janus van der Waals heterostructures composed of and (where X Y: S, Se; A B: Ga, In) over a ferroelectric monolayer. The results demonstrate that an external electric field effectively modulates out-of-plane ferroelectric polarization. First, the most stable stacking configuration of the heterostructure is identified through structural optimization. Subsequently, by performing first-principles calculations, systematically the stability of the structure, the electric potential, plane-averaged charge density distribution, and the electronic band structures are evaluated. The effective mass is calculated for the conduction band valleys, revealing that the valley exhibits the lowest effective mass. Notably, switching the polarization state from down to up in these heterostructures induces a significant bandgap reduction, suggesting strong electronic properties tunability. The heterostructures exhibit robust spontaneous polarization with substantial energy barriers, enabling efficient phase switching for practical applications. These findings highlight the exceptional potential of the Janus-type heterostructure for non-volatile ferroelectric memory and polarization-driven electronic devices, paving the way for next-generation functional materials. • Novel Ferroelectric Heterostructures: We propose and systematically investigate new Janus-type van der Waals heterostructures (In2XY/In2Se3 and ABSe2/In2Se3) that exhibit robust intrinsic out-of-plane ferroelectricity. • Electrically Tunable Properties: Ferroelectric polarization switching from “down” to “up” significantly reduces the electronic band gap and modulates carrier effective masses, enabling field-tunable electronic and optoelectronic applications. • Low-Barrier Switching Pathway: The heterostructures exhibit low energy barriers (31–72 meV) for polarization reversal via intermediate phases, indicating switchability under a practical external electric field. • Enhanced Polarization and Interface Control: The net out-of-plane 2D polarization reaches large magnitudes (up to C/m in GaInSe2/In2Se3) and can be either reversible (e.g., In2SSe/In2Se3) or pinned in sign (e.g., GaInSe2/In2Se3) depending on the strength of the built-in interfacial polarity and screening.
Rajabi-Maram et al. (Wed,) studied this question.