Spontaneous structural deformation of MoS2 nanoribbons in Au(111)/ MoS2/ Au(111) heterojunctions

Abstract

Using first-principles simulations, we demonstrate that MoS₂ nanoribbons adsorbed between two Au(111) electrodes in an Au/MoS₂/Au junction undergo spontaneous structural deformation involving bending and stretching. This deformation increases the mechanical strain energy within the nanoribbon but is energetically compensated by enhanced adsorption on the Au electrodes, owing to the larger contact areas formed in the deformed configuration. The influence of these spontaneous structural deformations on the electronic and transport properties of the junction is investigated using state-of-the-art first-principles methods. Our results reveal that deformation lowers the energies of conduction bands associated with edge states, leading to a pronounced narrowing of the bandgap in the deformed nanoribbons. For narrow nanoribbons with widths around 1.5 nm, this deformation markedly enhances the junction's conductivity by facilitating electron tunneling through the conducting localized edge states.