Reversible Logic Gates Achieved by Waveguide-Like Graphene Devices with Y-Shaped Channel and Titled Dual-Gate

Abstract

Graphene-based electronics have been developed over decades but are still limited by the inevitable trade-off between high carrier mobility and on-off ratio. The key bottleneck for high-performance graphene transistors is considered to stem from the absence of its bandgap, which leads to a large leakage current at off-state. Here, we demonstrate a waveguide-like device capable of electrical controllability for carrier flow in the desired direction by utilizing electron quantum optics based on Dirac Fermions in graphene. Our simulation results on the temporal evolution of the probability density of electron wavefunction indicate that the electron trajectories, i.e., the propagation direction and spread of electron wave packets, are highly sensitive to the magnitude of the applied gate potential in our proposed device consisting of Y-shaped graphene channel, tilted dual-gate, dual-drain, and quantum point contact. Guided current probability density exhibits a peak at a gate voltage of 0.44 V applied to the channel by the single gate in our dual-gate system. The gate voltage larger than 0.44 V is found to act as a blocking potential barrier with a higher refractive index. Simultaneous application of dual-gate impedes the propagation of Dirac Fermions since the refractive index abruptly increases in the overlapping gated region. Unlike conventional transistors, our proposed device manipulates the propagation direction of Dirac Fermions by tuning the gate voltage, which is promising to implement single-device reversible logic gates.