Size and strain modulation of dielectric constant on atomic bond relaxation

Abstract

From the viewpoints of bond order-length-strength correlation, core–shell structural model, and local bond average approach, we examined the size and strain effects on the dielectric constant of the transition metal dichalcogenides system. Consistency in theoretical results and reported values confirms that: (i) the surface atomic coordination number deficiency and bond energy perturbation dictate the size effect of the dielectric constant for nanometric semiconductors, and (ii) the bond elongation and softening lead to the tensile strain-induced rise in dielectric constant. The analytical function of dielectric constant dependence on size and strain is beyond the scope of available approaches, which not only provides a new understanding of the physical mechanism of the dielectric response to perturbations but also is helpful in the quantitative design of optoelectronic and photovoltaic nanodevices.