Tight-binding piezoelectric theory and electromechanical coupling correlations for transition metal dichalcogenide monolayers

摘要

The lack of inversion symmetry in semiconducting transition metal dichalcogenide monolayers (TMDMs) enables a considerable intrinsic piezoelectricity, which opens prospects for atomically thin piezotronics and optoelectronics. Here, based on the tight-binding (TB) approach and Berry phase expression for electronic polarization difference, we establish an atomic-scale TB theory for demonstrating piezoelectric physics in TMDMs. Using the TB piezoelectric theory, we predict the electronic Grueneisen parameter (EGP). which measures the electron-phonon couplings for TMDMs. By virtue of the constructed analytical piezoelectric model, we further reveal the correlation between the electronic contribution to piezoelectric coefficients and strain-induced pseudomagnetic gauge field (PMF). These predicted EGP and PMF for TMDMs are experimentally testable, and hence the TB piezoelectric model is an alternative theoretical framework for calculating electron-phonon interactions and PMF.