Journal article
Spin-orbit coupling and operation of multivalley spin qubits
Physical review. B, Vol.92(20), 201401(R)
11/05/2015
DOI: 10.1103/PhysRevB.92.201401
Abstract
Spin qubits composed of either one or three electrons are realized in a quantum dot formed at a Si/SiO2 interface in isotopically enriched silicon. Using pulsed electron-spin resonance, we perform coherent control of both types of qubits, addressing them via an electric field dependent g factor. We perform randomized benchmarking and find that both qubits can be operated with high fidelity. Surprisingly, we find that the g factors of the one-electron and three-electron qubits have an approximately linear but opposite dependence as a function of the applied dc electric field. We develop a theory to explain this g-factor behavior based on the spin-valley coupling that results from the sharp interface. The outer "shell" electron in the three-electron qubit exists in the higher of the two available conduction-band valley states, in contrast with the one-electron case, where the electron is in the lower valley. We formulate a modified effective mass theory and propose that intervalley spin-flip tunneling dominates over intravalley spin flips in this system, leading to a direct correlation between the spin-orbit coupling parameters and the g factors in the two valleys. In addition to offering all-electrical tuning for single-qubit gates, the g-factor physics revealed here for one-electron and three-electron qubits offers potential opportunities for different qubit control approaches.
Details
- Title: Subtitle
- Spin-orbit coupling and operation of multivalley spin qubits
- Creators
- M. Veldhorst - Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW 2052, AustraliaR. Ruskov - Physical Sciences (United States)C. H. Yang - Quantum Group (United States)J. C. C. Hwang - Univ New S Wales, Sch Elect Engn & Telecommun, Ctr Quantum Computat & Commun Technol, Sydney, NSW 2052, AustraliaF. E. Hudson - Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW 2052, AustraliaM. E. Flatte - University of IowaC. Tahan - Physical Sciences (United States)K. M. Itoh - Keio UniversityA. Morello - Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW 2052, AustraliaA. S. Dzurak - Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW 2052, Australia
- Resource Type
- Journal article
- Publication Details
- Physical review. B, Vol.92(20), 201401(R)
- DOI
- 10.1103/PhysRevB.92.201401
- ISSN
- 2469-9950
- eISSN
- 2469-9969
- Publisher
- Amer Physical Soc
- Number of pages
- 5
- Grant note
- W911NF-13-1-0024 / U.S. Army Research Office NSW Node of the Australian National Fabrication Facility FIRST JSPS; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT); Japan Society for the Promotion of Science CE110001027 / Australian Research Council NanoQuine Netherlands Organization for Scientific Research (NWO) through a Rubicon Grant; Netherlands Organization for Scientific Research (NWO) MEXT; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)
- Language
- English
- Date published
- 11/05/2015
- Academic Unit
- Electrical and Computer Engineering; Physics and Astronomy
- Record Identifier
- 9984429028302771
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