A mesoscopic ring as a XNOR gate: An exact result

TL;DR

This paper demonstrates how a mesoscopic ring can function as an XNOR logic gate by using quantum interference effects, with exact calculations showing the gate's response based on magnetic flux and gate voltages.

Contribution

It provides an exact theoretical model of an XNOR gate using a mesoscopic ring, highlighting its potential for nanoscale electronic logic devices.

Findings

High output current occurs when inputs are the same at specific magnetic flux.

The device exhibits clear XNOR gate behavior under certain conditions.

The model uses tight-binding and Green's function methods for precise analysis.

Abstract

We describe XNOR gate response in a mesoscopic ring threaded by a magnetic flux $\phi$. The ring is attached symmetrically to two semi-infinite one-dimensional metallic electrodes and two gate voltages, viz, $V_a$ and $V_b$, are applied in one arm of the ring which are treated as the inputs of the XNOR gate. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance-energy and current-voltage characteristics as functions of the ring-to-electrode coupling strength, magnetic flux and gate voltages. Our theoretical study shows that, for a particular value of $\phi$ ($=\phi_0/2$) ($\phi_0=ch/e$, the elementary flux-quantum), a high output current (1) (in the logical sense) appears if both the two inputs to the gate are the same, while if one but not both inputs are high (1), a low output current (0) results. It clearly exhibits the XNOR gate behavior and this aspect may be utilized in designing an electronic logic gate.