Department of Physics
Research, teaching and outreach in Physics at UW–Madison

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R. G. Herb Condensed Matter Seminars
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Coherent coupling between a quantum dot and a donor in silicon
Date: Thursday, April 6th
Time: 10:00 am
Place: 5310 Chamberlin Hall
Speaker: Patrick Harvey-Collard, Sandia National Labs
Abstract: Individual donors and quantum dots in silicon chips are used as bits of quantum information with different but complementary advantages. In this work, we show that these two qubit systems can be combined by demonstrating the coherent interaction of a 31P donor electron with the electron of a metal-oxide-semiconductor quantum dot. We form a qubit from the spin singlet and triplet states of the two-electron system. We show that the donor nuclear spin drives coherent rotations between the electronic qubit states through the contact hyperfine interaction. This provides every key element for compact two-electron spin qubits requiring only a single dot and no additional magnetic field gradients, as well as a means to interact with the nuclear spin qubit. This system furthermore introduces an engineered path to couple donors together, alleviating the need for challenging atomic-precision fabrication and providing a scalable path to multi-donor qubit systems.



In this talk, I will also discuss our advances in engineering the valley splitting and the shell filling of QDs to overcome the system’s challenges. I will present a scheme for high fidelity spin readout that combines the advantages of the Pauli blockade and spin 1/2 readouts.



This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE under contract DE-AC04-94AL85000.​

Host: Coppersmith
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