211 research outputs found
Fractional periodic persistent current in a twisted normal metal loop: an exact result
We explore a novel mechanism for control of periodicity in persistent current
in a twisted normal metal loop threaded by a magnetic flux . A simple
tight-binding model is used to describe the system. Quite interestingly we see
that, depending on the number of twist , the persistent current exhibits
(, the elementary flux-quantum) periodicity. Such
fractional periodicity provides a new finding in the study of persistent
current.Comment: 7 pages, 4 figure
Implementation of classical logic gates at nano-scale level using magnetic quantum rings: A theoretical study
We explore the possibilities of designing classical logic gates at nano-scale
level using magnetic quantum rings. A single ring is used for designing OR,
NOT, XOR, XNOR and NAND gates, while AND and NOR gate responses are achieved
using two such rings and in all the cases each ring is threaded by a magnetic
flux which plays the central role in the logic gate operation. We adopt
a simple tight-binding Hamiltonian to describe the model where a magnetic
quantum ring is attached to two semi-infinite one-dimensional non-magnetic
electrodes. Based on single particle Green's function formalism all the
calculations which describe two-terminal conductance and current through the
quantum ring are performed numerically. The analysis may be helpful in
fabricating mesoscopic or nano-scale logic gates.Comment: 19 pages, 25 figures, 7 table
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