Charge-state conditional operation of a spin qubit

Van Weperen, I. and Armstrong, B. D. and Laird, E A and Medford, J and Marcus, C M and Hanson, M P and Gossard, A C (2011) Charge-state conditional operation of a spin qubit. Physical review letters, 107 (3). ISSN 1079-7114

Abstract

We report coherent operation of a singlet-triplet qubit controlled by the spatial arrangement of two confined electrons in an adjacent double quantum dot that is electrostatically coupled to the qubit. This four-dot system is the specific device geometry needed for two-qubit operations of a two-electron spin qubit. We extract the strength of the capacitive coupling between qubit and adjacent double quantum dot and show that the present geometry allows fast conditional gate operation, opening pathways toward implementation of a universal set of gates for singlet-triplet spin qubits.