Using split-gate structures to explore the implementation of a coupled-electron-waveguide qubit scheme

We explore the use of the split-gate method to implement coupled-electron waveguides (CEWs), for possible application as a scalable qubit in quantum computing. Electron switching in these structures is found to be strongly influenced by structural asymmetry, which appears to arise quite naturally when using the split-gate method to implement complicated nanostructures. The consequences of the asymmetry are shown to depend strongly on the manner in which the input and output ports of the device are configured, and include unwanted decoherence due to geometry-induced scattering of electrons into regions outside of the classical current path. An approach to eliminating the influence of this asymmetry, to allow the realization of a 'balanced qubit', is also explored.