Journal article

Delocalized Oxygen as the Origin of Two-Level Defects in Josephson Junctions

Timothy C DuBois, Manolo C Per, Salvy P Russo, Jared H Cole

PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2013

Abstract

One of the key problems facing superconducting qubits and other Josephson junction devices is the decohering effects of bistable material defects. Although a variety of phenomenological models exist, the true microscopic origin of these defects remains elusive. For the first time we show that these defects may arise from delocalization of the atomic position of the oxygen in the oxide forming the Josephson junction barrier. Using a microscopic model, we compute experimentally observable parameters for phase qubits. Such defects are charge neutral but have nonzero response to both applied electric field and strain. This may explain the observed long coherence time of two-level defects in the ..

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University of Melbourne Researchers

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Funding Acknowledgements

This work was supported by an award under the Merit Allocation Scheme on the NCI National Facility at the ANU.