T. A. Oliveira, J. Coutinho, M. J. Rayson and P. R. Briddon; University of Aveiro Research Day 2013 (Aveiro – Portugal, 2013-06-19)
The static dielectric constant of semiconductor nanostructures has been the subject of intense research and discussion for both fundamental and technological reasons. This quantity is often predicted by means of expensive density-functional perturbation methods
[su_tooltip style=”light” position=”north” shadow=”yes” rounded=”yes” title=”Reference” content=”G. Onida et al., Rev. Mod. Phys. 74, 601 (2002)”][/su_tooltip]
or in the dipole approximation with help of transition matrix elements between occupied and empty states. The latter option carries the extra difficulty in that it needs an accurate description of excited states, which is not the case when using popular density functional methods with a local or semi-local treatment to the exchange and correlation energy. Here we propose that the static dielectric constant of nano-objects can be obtained from the response of their ground state electron density to a background charge density that is introduced in charged periodic calculations. Such a charge can be that of an ion, ideally located at a remote position to the nanostructure. The method is applied to prototypical systems (ex. Si heterostructures and Si-nanocrystal superlattices), by using the electron density and electrostatic potential from standard density functional calculations.
University of Aveiro Research Day 2013 (Aveiro – Portugal, 2013-06-19)