Structural isomers, double wells, resonances, and Dirichlet decoupling

Wim Vanroose

We discuss the interaction between two resonant states in a quantum double-well structure. The behavior of the resonant states depends on the coupling between the wells, i.e., the height and width of the barrier that separates them. We distinguish a region with resonant tunneling and a region where the two resonances repel each other. The transition between the two regions is marked by a double pole of the S matrix.

Aysevil Salman Durmuşlar

Abstract Linear, nonlinear and total optical absorption coefficients and relative refractive index changes for both symmetric and asymmetric double V-shaped quantum well configurations formed within AlxGa1-xAs/GaAs heterostructure are theoretically investigated. Responses of these coefficients to well widths, barrier widths and concentration of aluminum within the barrier as well as applied external electromagnetic fields are the subject of this study. The electronic spectra of the structures are obtained as a solution of Schrödinger equation with relevant potential and external agents in the framework of effective mass and envelope wave function approximations. The optical properties are calculated via the analytical expressions obtained by iterative solutions within compact density matrix approach. Although increasing barrier width and aluminum concentration act similar significant red shifting on the referred coefficients for both symmetric and asymmetric double V-shaped wells, the varying well widths acts differently for each configuration. Widening both wells in symmetric case moves the resonance peaks to lower energies, while the rise on only one well carries the resonance peaks to higher energies for asymmetric case. Enhancing both the electric and magnetic fields shift the resonance peaks to the blue for symmetric and also asymmetric wells. High dependency of the optical properties to the structural parameters and external electromagnetic fields as well as asymmetry of the wells is presented here in detail.

Frank H. Read

Esin KASAPOĞLU, S. Şakiroğlu, H. Sarı +2 more

In this study, the first-order linear, third-order nonlinear, and total absorption coefficients for the intersubband transition between the two lower-lying electronic levels in both symmetric and asymmetric double Morse quantum wells under the non-resonant high-frequency intense laser field are investigated. The study takes into account the effects of the structure parameters. The results show that the electronic and also accordingly optical properties of the structures which we focus on can be adjustable to obtain a convenient response to certain studies or purposes by changing the applied external field and optical intensity as well as structure parameters.

Frederic R. Morgenthaler