Enhanced piezoelectricity and electronic band structure transition assisted by atomic shift in MoS2 monolayer

TL;DR

This paper demonstrates that a single atomic shift in MoS2 monolayers can significantly enhance piezoelectricity and alter electronic band structures, enabling tailored mechano-electrical properties for advanced applications.

Contribution

It introduces a novel approach of atomic shifting to engineer piezoelectric and electronic properties in MoS2 monolayers, which was not previously explored.

Findings

Piezoelectric coefficient (e11) increased by 18% with atomic shift.

Atomic shift created new energy levels within the bandgap.

Band structure was significantly modified by atomic shifts.

Abstract

Piezoelectricity appears in the inversion asymmetric crystal that converts mechanical deformational force to electricity. Two-dimensional transition metal dichalcolgenide (TMDC) monolayers exhibit the piezoelectric effect due to the inversion asymmetry. The intrinsic piezoelectric coefficient (e11) of MoS2 is ~298 pC/m. For the single atomic shift of Mo of 20% along the armchair direction, the piezoelectric coefficient (e11) of MoS2 with 5x5 unit cells was enhanced up to 18%, and significantly modified the band structure. The single atomic shift in the MoS2 monolayer also induced new energy levels inside the forbidden bandgap. The defect-induced energy levels for a Mo atom shift along the armchair direction are relatively deeper than the energy levels for a S atom shift along the same direction. It indicates that the piezoelectricity and band structure of MoS2 can be engineered by a single atomic shift in the monolayer with multi unit cells for mechano-electrical applications.