Giant persistent currents in the open Aharonov-Bohm rings

Abstract

We investigate persistent currents in the Aharonov-Bohm rings coupled to external leads. For a contacted double-ring structure, it is found that the flux-independent perfect transmission occurs at klϭ/2, where k is the wave number and l the half length of a single ring. The flux-independent perfect reflection occurs at kl ϭ0. These repeat with period in kl. There are singular points in the flux at f ϭ1/2 for the flux-independent perfect transmission where f means the ratio of a flux to the flux quantum and at f ϭ0 for the reflection. These repeat with period 1 in f. A giant persistent current is generated whenever kl approaches these singular points.

Properties of transmission of electron in coupled rings

“…Since the discovery of the persistent current, there have been many studies on single ring [2][3][4][5], coupled rings [6,7], connected rings [8] and rings with multiple arms [9]. This research shows that the persistent current runs not only in isolated ring but also in that with external leads, i.e., in open systems [2,3,10,11].…”

Fractal Property of Band Branching in Fibonacci Mesoscopic Rings

“…[1][2][3]7,13,14,19) Figure 8 shows the transmission spectra and corresponding band gaps of the S v FARs with F ¼ 0:7, v ¼ 4, 6, and 9. In Fig.…”

“…For these mesoscopic devices, the interference effects become important. The physical properties of the mesoscopic rings have attracted much attention since the investigation of the energy spectrum in the normal-metal ring by Büttiker et al 1) Interesting quantum coherent phenomena in the ring systems have been studied by various experimental and theoretical works, including the Josephshon-like effects in the closed ring driven by an external magnetic flux, quantum oscillations in the electric resistance of the ring connected by external leads, 2) resonant transmission and persistent currents in double 3) and periodical rings, 4) localization in disorder array, 5) and delocalization in correlated array of rings. 6) Recently, localizationdelocalization of quantum transport in a quasiperiodic array has received intensive interest since the discovery of quasicrystals.…”

Electronic Transport Properties of a Four-Terminal Mesoscopic Structure With a Ring

“…6 Pareek et al 7 have investigated the effect of impurities on the current magnification in mesoscopic open rings. Yi et al 8 have investigated the giant persistent currents in the open Aharonov-Bohm rings. We have noticed that the systems studied in the works mentioned above are only one electronic outgoing exit.…”