Bükümlü ışıkların nanoboyutlu yarıiletken ve moleküler yapılardaki kuantum elektron dinamiği üzerindeki etkisi / The effect of twisted light on quantum electron dynamics of nanoscale semiconductor and molecular structures

Abstract

In this study, the effect of spin and orbital angular momentum carrying laser light on electron dynamics of circularly or spherically symmetric molecular and semiconductor clusters has been investigated. The electronic structure of molecular clusters has been calculated by Gaussian 09. Finite difference method and effective mass technique have been used for electronic structure calculation of semiconductor clusters. In order for some comparative studies, VASP has been performed to calculate the bulk electronic structure of semiconductors. The interaction between twisted light and nanoscale clusters has been investigated by using the codes which we have written in Mathematica 9.0, Fortran and C++. Photoinduced current and magnetic field, which are result of the transfer of light’ spin and orbital angular momentum to the structures, have been obtained and introduced comparatively. Although the recent theoretical and experimental studies reported that circularly polarized light applied on aromatic molecules is able to induce a ring current in the range of nanoampere, we obtained important results as following. Twisted light is able to induce higher value of ring current. It is possible to increase the number of electrons which contributes to the induced ring current. It is also possible to manipulate the induced current by varying the parameters of twisted light. The number of electron excitations for single photon frequency can be increased by appropriate design of semiconductor clusters.