Magnetoconductance switching in an array of oval quantum dots

Abstract

Employing oval shaped quantum billiards connected by quantum wires as the building blocks of a linear quantum dot array, we calculate the ballistic magnetoconductance in the linear response regime. Optimizing the geometry of the billiards, we aim at a maximal finite- over zero-field ratio of the magnetoconductance. This switching effect arises from a relative phase change of scattering states in the oval quantum dot through the applied magnetic field, which lifts a suppression of the transmission characteristic for a certain range of geometry parameters. It is shown that a sustainable switching ratio is reached for a very low field strength, which is multiplied by connecting only a second dot to the single one. The impact of disorder is addressed in the form of remote impurity scattering, which poses a temperature dependent lower bound for the switching ratio, showing that this effect should be readily observable in experiments.Comment: 11 pages, 8 figure

Local symmetries in one-dimensional quantum scattering

“…Without the defects, the transmission properties of the uniform array are determined by its unit cell [26], which also defines the scale of local symmetry. Due to coupling of the degenerate resonant levels of adjacent identical resonators, a uniform N -scatterer array exhibits (N − 1)-fold split PTRs [26,27], which saturate into transmission bands for increasing N. As we see, the presence of aperiodicity [28] distorts the precursors of the energy bands [1,29] and lowers the resonances in T (E) from unity because of the induced asymmetry [6]. Nevertheless, the decomposition into resonators [particularly of type (c)] containing multiple barriers reveals the possibility of PTRs, as explained above, owing to the locally symmetric ρ kr of irreducible resonant states.…”

Magnetic forces and localized resonances in electron transfer through quantum rings

“…The Fano resonances are extensively studied for quantum rings and open quantum dots side coupled to the channel [12,13,15,14,16,17] as well as for potential cavities embedded within the channel [18,19]. In order to determine the localized resonances we employ the stabilization method [20] in the version proposed by Mandelshtam and coworkers [21].…”

Coherent magnetotransport and time-dependent transport through split-gated quantum constrictions

“…[10][11][12][13] The conductance G is a fundamental property of quasi-one-dimensional systems with values close to integer multiples of twice the quantum unit of conductance G 0 =2e 2 / h, where e denotes the charge of an electron, the factor of 2 accounts for spin degeneracy, and h is Planck's constant. Moreover, the conductance depends sensitively on the particular arrangement of scatterers as well as the applied external fields in the mesoscopic system.…”