The Effect Of Impurity Potential Varying Harmonically In Time On The Transport Property Of The Semiconductor Superlattice

In this thesis, firstly some basic theories of semiconductor superlattice have been introduced. Then, the diagonal components of Green function of single particle of the system which is the tight-binding model under influence of the external electric field are derived. The local density of states is obtained through Green function. We study a dc-biased tight-binding model with single impurity potential varying harmonically in time. Floquet-Green for the system has been given in the framework of U(t,t) methods. The continued fraction expression for the density of states is obtained by Floquet-Green function approach. The numerical calculation of the local density of states through the expression has been given. The local density of states for this system and the behavior of the localized states as a function of parameters that characterize the system have been investigated. The calculation of the local density of states shows that the new states will emerge between the resonant Wannier-Stark states. Finally, we study dynamical evolution of this system using the numerical calculation.