Modeling Circular Current Resonances in a 6-Quantum Dot Ring

A nanoscale ring configuration, modeled as a 6-quantum dot ring, is investigated computationally to study the behavior of circular current resonances. The computational method utilizes the tight-binding approximation to the Schrodinger Equation to solve for the transmission and circular transmission as a function of electron energy, external magnetic flux, and other system parameters. Large amplitude resonances of the circular transmission are found to occur when two poles of the transmission are separated along the imaginary axis. These resonances demonstrate a high degree of flux-sensitivity at specific energy values and flux ranges. Flux-dependent interference between the transmission poles and zeros in the complex energy plane affects the magnitude of the circular transmission resonance amplitudes. The circular transmission and its corresponding current-vs.-voltage characteristics may serve as a nano-sensor, providing a higher degree of correlation with the external flux than is observable with the normal transmission alone.