Narrow Localized Electronic States Induced by Defective Electronic Comb-Like Quantum Wires

Abstract

A theoretical study is done using the transfer matrix method (TMM) to study the propagation of electrons waves in a one-dimensional electronic comb-like waveguides (ECWGs) quantum wires structure composed of a semiconductor segment (GaAs) grafted at its extremity by one semiconductor resonator (GaAlAs). For the first time, we have proposed a simple system with a single GaAlAs resonator embedded between two semi-infinite electronic waveguides. As a result, the energies of the corresponding resonator eigenmodes shift to lower energies as the resonator length increases. The resulting eigenmodes are characterized by high transmission rates but very low-quality factor values, which highlight the importance of the periodicity of the system. Further, in order to create localized electronic defect states with higher quality factors in the bandgaps, a defective system is exanimated. Indeed, a defective segment and resonator are inserted into a perfect system. This defective system can create localized electronic defect states in the electronic bandgaps. The analysis of the transmission spectra and the maximum transmission of these defects states shows a shift to lower energies by increasing the length of the defects. These localized defect states can interact with each other by exchanging energy. Furthermore, it has been shown that the number of localized states induced by the presence of these defects, depends on the defect lengths parameters.