Modeling of Dual-Gate GaAs-Nanowire FET for Room Temperature Charge-Qubit Operation: An NEGF Approach

The current work investigates the performance of dual-gate GaAs-nanowire FET as a charge-qubit device operating at room temperature. In compatibility with the state-of-the-art classical bit technology, it is shown that the single gate of a nanowire FET can be replaced by two localized gates to achieve such charge-qubit operation. On application of relevant biases to the localized gates, two voltage tunable quantum dots are created within the nanowire channel with electrostatically controlled single-state-occupancy and inter-dot coupling leading to charge-qubit operation at room temperature. The associated electron transport is theoretically modeled on the basis of non-equilibrium Greens function (NEGF) formalism. The initialization and manipulation for qubit operation are performed by applying suitable gate voltages, whereas the measurement is executed by applying a small drain bias to obtain a pulse current of ~pA order. A ~25 MHz frequency of coherent oscillation is observed for the qubit and a characteristic decay time of ~ 70 ns is achieved. The results suggest that such dual gate nanowire FET is a promising architecture for charge-qubit operation at room temperature.