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Sigillito AJ, Tyryshkin AM, Schenkel T, Houck AA, Lyon SA. All-electric control of donor nuclear spin qubits in silicon. NATURE NANOTECHNOLOGY 2017; 12:958-962. [PMID: 28805818 DOI: 10.1038/nnano.2017.154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
The electronic and nuclear spin degrees of freedom of donor impurities in silicon form ultra-coherent two-level systems that are potentially useful for applications in quantum information and are intrinsically compatible with industrial semiconductor processing. However, because of their smaller gyromagnetic ratios, nuclear spins are more difficult to manipulate than electron spins and are often considered too slow for quantum information processing. Moreover, although alternating current magnetic fields are the most natural choice to drive spin transitions and implement quantum gates, they are difficult to confine spatially to the level of a single donor, thus requiring alternative approaches. In recent years, schemes for all-electrical control of donor spin qubits have been proposed but no experimental demonstrations have been reported yet. Here, we demonstrate a scalable all-electric method for controlling neutral 31P and 75As donor nuclear spins in silicon. Using coplanar photonic bandgap resonators, we drive Rabi oscillations on nuclear spins exclusively using electric fields by employing the donor-bound electron as a quantum transducer, much in the spirit of recent works with single-molecule magnets. The electric field confinement leads to major advantages such as low power requirements, higher qubit densities and faster gate times. Additionally, this approach makes it possible to drive nuclear spin qubits either at their resonance frequency or at its first subharmonic, thus reducing device bandwidth requirements. Double quantum transitions can be driven as well, providing easy access to the full computational manifold of our system and making it convenient to implement nuclear spin-based qudits using 75As donors.
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Affiliation(s)
- Anthony J Sigillito
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Alexei M Tyryshkin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Thomas Schenkel
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrew A Houck
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Stephen A Lyon
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Tocchio LF, Arrigoni F, Sorella S, Becca F. Assessing the orbital selective Mott transition with variational wave functions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:105602. [PMID: 26881997 DOI: 10.1088/0953-8984/28/10/105602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We study the Mott metal-insulator transition in the two-band Hubbard model with different hopping amplitudes t1 and t2 for the two orbitals on the two-dimensional square lattice by using non-magnetic variational wave functions, similarly to what has been considered in the limit of infinite dimensions by dynamical mean-field theory. We work out the phase diagram at half filling (i.e. two electrons per site) as a function of R = t2/t1 and the on-site Coulomb repulsion U, for two values of the Hund's coupling J = 0 and J/U = 0.1. Our results are in good agreement with previous dynamical mean-field theory calculations, demonstrating that the non-magnetic phase diagram is only slightly modified from infinite to two spatial dimensions. Three phases are present: a metallic one, for small values of U, where both orbitals are itinerant; a Mott insulator, for large values of U, where both orbitals are localized because of the Coulomb repulsion; and the so-called orbital-selective Mott insulator (OSMI), for small values of R and intermediate Us, where one orbital is localized while the other one is still itinerant. The effect of the Hund's coupling is two-fold: on one side, it favors the full Mott phase over the OSMI; on the other side, it stabilizes the OSMI at larger values of R.
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Affiliation(s)
- Luca F Tocchio
- Democritos National Simulation Center, Istituto Officina dei Materiali del CNR, and SISSA-International School for Advanced Studies, Via Bonomea 265, I-34136 Trieste, Italy
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Berski F, Hübner J, Oestreich M, Ludwig A, Wieck AD, Glazov M. Interplay of Electron and Nuclear Spin Noise in n-Type GaAs. PHYSICAL REVIEW LETTERS 2015; 115:176601. [PMID: 26551132 DOI: 10.1103/physrevlett.115.176601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Indexed: 06/05/2023]
Abstract
We present spin-noise spectroscopy measurements on an ensemble of donor-bound electrons in ultrapure GaAs:Si covering temporal dynamics over 6 orders of magnitude from milliseconds to nanoseconds. The spin-noise spectra detected at the donor-bound exciton transition show the multifaceted dynamical regime of the ubiquitous mutual electron and nuclear spin interaction typical for III-V-based semiconductor systems. The experiment distinctly reveals the finite Overhauser shift of an electron spin precession at zero external magnetic field and a second contribution around zero frequency stemming from the electron spin components parallel to the nuclear spin fluctuations. Moreover, at very low frequencies, features related with time-dependent nuclear spin fluctuations are clearly resolved making it possible to study the intricate nuclear spin dynamics at zero and low magnetic fields. The findings are in agreement with the developed model of electron and nuclear spin noise.
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Affiliation(s)
- Fabian Berski
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, D-30167 Hannover, Germany
| | - Jens Hübner
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, D-30167 Hannover, Germany
| | - Michael Oestreich
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, D-30167 Hannover, Germany
| | - Arne Ludwig
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - A D Wieck
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Mikhail Glazov
- Ioffe Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
- Spin Optics Laboratory, St. Petersburg State University, Ul'anovskaya 1, Peterhof, 198504 St. Petersburg, Russia
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Scarlino P, Kawakami E, Ward DR, Savage DE, Lagally MG, Friesen M, Coppersmith SN, Eriksson MA, Vandersypen LMK. Second-Harmonic Coherent Driving of a Spin Qubit in a Si/SiGe Quantum Dot. PHYSICAL REVIEW LETTERS 2015; 115:106802. [PMID: 26382693 DOI: 10.1103/physrevlett.115.106802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Indexed: 06/05/2023]
Abstract
We demonstrate coherent driving of a single electron spin using second-harmonic excitation in a Si/SiGe quantum dot. Our estimates suggest that the anharmonic dot confining potential combined with a gradient in the transverse magnetic field dominates the second-harmonic response. As expected, the Rabi frequency depends quadratically on the driving amplitude, and the periodicity with respect to the phase of the drive is twice that of the fundamental harmonic. The maximum Rabi frequency observed for the second harmonic is just a factor of 2 lower than that achieved for the first harmonic when driving at the same power. Combined with the lower demands on microwave circuitry when operating at half the qubit frequency, these observations indicate that second-harmonic driving can be a useful technique for future quantum computation architectures.
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Affiliation(s)
- P Scarlino
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - E Kawakami
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - D R Ward
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D E Savage
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M G Lagally
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Mark Friesen
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S N Coppersmith
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M A Eriksson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L M K Vandersypen
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
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van Bree J, Silov AY, Koenraad PM, Flatté ME. Spin-orbit-induced circulating currents in a semiconductor nanostructure. PHYSICAL REVIEW LETTERS 2014; 112:187201. [PMID: 24856716 DOI: 10.1103/physrevlett.112.187201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Circulating orbital currents produced by the spin-orbit interaction for a single electron spin in a quantum dot are explicitly evaluated at zero magnetic field, along with their effect on the total magnetic moment (spin and orbital) of the electron spin. The currents are dominated by coherent superpositions of the conduction and valence envelope functions of the electronic state, are smoothly varying within the quantum dot, and are peaked roughly halfway between the dot center and edge. Thus the spatial structure of the spin contribution to the magnetic moment (which is peaked at the dot center) differs greatly from the spatial structure of the orbital contribution. Even when the spin and orbital magnetic moments cancel (for g=0) the spin can interact strongly with local magnetic fields, e.g., from other spins, which has implications for spin lifetimes and spin manipulation.
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Affiliation(s)
- J van Bree
- PSN, COBRA Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - A Yu Silov
- PSN, COBRA Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - P M Koenraad
- PSN, COBRA Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - M E Flatté
- PSN, COBRA Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands and Department of Physics and Astronomy and Optical Science and Technology Center, University of Iowa, Iowa City, Iowa 52242, USA
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Brovko OO, Ruiz-Díaz P, Dasa TR, Stepanyuk VS. Controlling magnetism on metal surfaces with non-magnetic means: electric fields and surface charging. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:093001. [PMID: 24523356 DOI: 10.1088/0953-8984/26/9/093001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review the state of the art of surface magnetic property control with non-magnetic means, concentrating on metallic surfaces and techniques such as charge-doping or external electric field (EEF) application. Magneto-electric coupling via EEF-based charge manipulation is discussed as a way to tailor single adatom spins, exchange interaction between adsorbates or anisotropies of layered systems. The mechanisms of paramagnetic and spin-dependent electric field screening and the effect thereof on surface magnetism are discussed in the framework of theoretical and experimental studies. The possibility to enhance the effect of EEF by immersing the target system into an electrolyte or ionic liquid is discussed by the example of substitutional impurities and metallic alloy multilayers. A similar physics is pointed out for the case of charge traps, metallic systems decoupled from a bulk electron bath. In that case the charging provides the charge carrier density changes necessary to affect the magnetic moments and anisotropies in the system. Finally, the option of using quasi-free electrons rather than localized atomic spins for surface magnetism control is discussed with the example of Shockley-type metallic surface states confined to magnetic nanoislands.
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Affiliation(s)
- Oleg O Brovko
- Max-Planck Institut für Mikrostrukturphysik, Halle, Germany
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Abstract
The sensitive dependence of a semiconductor's electronic, optical and magnetic properties on dopants has provided an extensive range of tunable phenomena to explore and apply to devices. Recently it has become possible to move past the tunable properties of an ensemble of dopants to identify the effects of a solitary dopant on commercial device performance as well as locally on the fundamental properties of a semiconductor. New applications that require the discrete character of a single dopant, such as single-spin devices in the area of quantum information or single-dopant transistors, demand a further focus on the properties of a specific dopant. This article describes the huge advances in the past decade towards observing, controllably creating and manipulating single dopants, as well as their application in novel devices which allow opening the new field of solotronics (solitary dopant optoelectronics).
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Affiliation(s)
- Paul M Koenraad
- COBRA Inter-University Research Institute, Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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