Journal article

Valley Filtering in Spatial Maps of Coupling between Silicon Donors and Quantum Dots

Joe Salfi, Benoit Voisin, Archana Tankasala, J Bocquel, M Usman, Michelle Simmons, Lloyd Hollenberg, Rajib Rahman, Sven Rogge

Physical Review X | American Physical Society | Published : 2018


Exchange coupling is a key ingredient for spin-based quantum technologies since it can be used to entangle spin qubits and create logical spin qubits. However, the influence of the electronic valley degree of freedom in silicon on exchange interactions is presently the subject of important open questions. Here we investigate the influence of valleys on exchange in a coupled donor–quantum-dot system, a basic building block of recently proposed schemes for robust quantum information processing. Using a scanning tunneling microscope tip to position the quantum dot with sub-nm precision, we find a near monotonic exchange characteristic where lattice-aperiodic modulations associated with valley d..

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Awarded by Australian Research Council

Funding Acknowledgements

The authors would like to thank D. Culcer for helpful discussions. We acknowledge support from the ARC Centre of Excellence for Quantum Computation and Communication Technology (CE110001027), and partial support from the U.S. Army Research Office (W911NF-08- 1-0527). J. S. acknowledges support from an ARC DECRA fellowship (DE160101490). The authors acknowledge the use of computational resources from NanoHUB, the Network for Computational Nanotechnology at Purdue University, and from the Australian Government through the Pawsey Supercomputing Centre under the National Computational Merit Allocation Scheme (NCMAS). This work used the Extreme Science and Engineering Discovery Environment (XSEDE) ECS150001, which is supported by National Science Foundation Grant No. ACI-1548562