Stacking-Directed Polarization and Excitonic Engineering in MoS${}_2$/MoSe${}_2$ van der Waals Heterostructures

Abstract

The stacking-dependent polarization and excitonic response of MoS${}_2$/MoSe${}_2$ heterostructures were investigated using GW+BSE many-body perturbation theory. While homobilayer MoS${}_2$ exhibited a switchable interlayer dipole driven by registry-induced symmetry breaking, the MoS${}_2$/MoSe${}_2$ hetero-interface remained pinned by the intrinsic chemical potential mismatch between sulfur and selenium. In 2L-MoS${}_2$/MoSe${}_2$ trilayers, the stacking sequence enabled a deterministic control of photogenerated electrons between the central and bottom MoS${}_2$ layers, governed by internal electric fields and quasiparticle band-edge shifts of 60--70~meV. Our calculations predicted a 36~meV interlayer excitonic shift, in remarkable agreement with recent experiments. These results elucidate the microscopic link between atomic registry and many-body interactions, establishing transition metal dichalcogenide trilayers as a potential platform for sliding ferroelectricity and programmable optoelectronic functionalities.

This version contains extended discussion of trilayer properties