  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 Green s
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.
