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 $\phi$ 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.