||Systems with spin-orbit interaction have significant potential for solid-state quantum computation. Coupling between the orbital angular momentum and the spin in the valence band of silicon opens the possibility for rapid all-electrical manipulation of an acceptor-bound spin-orbit state, while selection rules can provide a qubit basis that is protected from decoherence by time-reversal symmetry. Building on the seminal work of Kane, I will present a design for an acceptor-based quantum computer where the transitions between the working levels of the qubit can be switched on and off by manipulating the acceptor wave function. The crucial parameter here is the interface-induced energy splitting between the two Kramers doublets that make up the ground state of the undisturbed acceptor wave function. Based on fully atomistic tight binding simulations and low-temperature scanning tunnelling spectroscopy interface-split Kramers doublets of individual boron acceptors near a silicon surface are visualised and identified. The electron temperature in the sample is used as a reference to directly determine the energy splitting between the Kramers doublets as a function of acceptor depth which is found to be in good agreement with calculations. Finally, the observed energy splitting of ~4 meV effectively protects acceptor-based qubit from decoherence.
About the Speaker: After graduating with a Master’s Degree in Applied Physics at the Delft University of Technology in the Netherlands I obtained my PhD Degree in Delft in 2012 studying Single Atom Electronics in the group of Prof. dr. Sven Rogge. During my time as a PhD student I moved to Sydney, Australia where I am currently working as a Postdoctoral Fellow at the Centre for Quantum Computation and Communication Technology at the University of New South Wales. My research focusses on studying single dopant atoms in silicon using Scanning Tunneling Spectroscopy with the emphasis on using dopants as building blocks for quantum computation.