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Camenzind LC, Svab S, Stano P, Yu L, Zimmerman JD, Gossard AC, Loss D, Zumbühl DM. Isotropic and Anisotropic g-Factor Corrections in GaAs Quantum Dots. PHYSICAL REVIEW LETTERS 2021; 127:057701. [PMID: 34397233 DOI: 10.1103/physrevlett.127.057701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 04/29/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
We experimentally determine isotropic and anisotropic g-factor corrections in lateral GaAs single-electron quantum dots. We extract the Zeeman splitting by measuring the tunnel rates into the individual spin states of an empty quantum dot for an in-plane magnetic field with various strengths and directions. We quantify the Zeeman energy and find a linear dependence on the magnetic field strength that allows us to extract the g factor. The measured g factor is understood in terms of spin-orbit interaction induced isotropic and anisotropic corrections to the GaAs bulk g factor. Experimental detection and identification of minute band-structure effects in the g factor is of significance for spin qubits in GaAs quantum dots.
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Affiliation(s)
- Leon C Camenzind
- Department of Physics, University of Basel, Basel 4056, Switzerland
| | - Simon Svab
- Department of Physics, University of Basel, Basel 4056, Switzerland
| | - Peter Stano
- Center for Emergent Matter Science, RIKEN, Saitama 351-0198, Japan
- Institute of Physics, Slovak Academy of Sciences, 845 11 Bratislava, Slovakia
| | - Liuqi Yu
- Department of Physics, University of Basel, Basel 4056, Switzerland
| | - Jeramy D Zimmerman
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Arthur C Gossard
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Daniel Loss
- Department of Physics, University of Basel, Basel 4056, Switzerland
- Center for Emergent Matter Science, RIKEN, Saitama 351-0198, Japan
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2
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Stein RM, Barcikowski ZS, Pookpanratana SJ, Pomeroy JM, Stewart MD. Alternatives to aluminum gates for silicon quantum devices: defects and strain. JOURNAL OF APPLIED PHYSICS 2021; 130:10.1063/5.0036520. [PMID: 36733463 PMCID: PMC9890375 DOI: 10.1063/5.0036520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/16/2021] [Indexed: 06/13/2023]
Abstract
Gate-defined quantum dots (QD) benefit from the use of small grain size metals for gate materials because it aids in shrinking the device dimensions. However, it is not clear what differences arise with respect to process-induced defect densities and inhomogeneous strain. Here, we present measurements of fixed charge, Q f , interface trap density, D it , the intrinsic film stress, σ, and the coefficient of thermal expansion, α as a function of forming gas anneal temperature for Al, Ti/Pd, and Ti/Pt gates. We show D it is minimal at an anneal temperature of 350 °C for all materials but Ti/Pd and Ti/Pt have higher Q f and D it compared to Al. In addition, σ and α increase with anneal temperature for all three metals with α larger than the bulk value. These results indicate that there is a tradeoff between minimizing defects and minimizing the impact of strain in quantum device fabrication.
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Affiliation(s)
- Ryan M. Stein
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Z. S. Barcikowski
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - S. J. Pookpanratana
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - J. M. Pomeroy
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - M. D. Stewart
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
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3
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Ansaloni F, Chatterjee A, Bohuslavskyi H, Bertrand B, Hutin L, Vinet M, Kuemmeth F. Single-electron operations in a foundry-fabricated array of quantum dots. Nat Commun 2020; 11:6399. [PMID: 33328466 PMCID: PMC7744547 DOI: 10.1038/s41467-020-20280-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 11/23/2020] [Indexed: 11/27/2022] Open
Abstract
Silicon quantum dots are attractive for the implementation of large spin-based quantum processors in part due to prospects of industrial foundry fabrication. However, the large effective mass associated with electrons in silicon traditionally limits single-electron operations to devices fabricated in customized academic clean rooms. Here, we demonstrate single-electron occupations in all four quantum dots of a 2 x 2 split-gate silicon device fabricated entirely by 300-mm-wafer foundry processes. By applying gate-voltage pulses while performing high-frequency reflectometry off one gate electrode, we perform single-electron operations within the array that demonstrate single-shot detection of electron tunneling and an overall adjustability of tunneling times by a global top gate electrode. Lastly, we use the two-dimensional aspect of the quantum dot array to exchange two electrons by spatial permutation, which may find applications in permutation-based quantum algorithms.
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Affiliation(s)
- Fabio Ansaloni
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Anasua Chatterjee
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Heorhii Bohuslavskyi
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
| | | | | | - Maud Vinet
- CEA, LETI, Minatec Campus, Grenoble, France
| | - Ferdinand Kuemmeth
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark.
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4
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Patlatiuk T, Scheller CP, Hill D, Tserkovnyak Y, Egues JC, Barak G, Yacoby A, Pfeiffer LN, West KW, Zumbühl DM. Edge-State Wave Functions from Momentum-Conserving Tunneling Spectroscopy. PHYSICAL REVIEW LETTERS 2020; 125:087701. [PMID: 32909808 DOI: 10.1103/physrevlett.125.087701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We perform momentum-conserving tunneling spectroscopy using a GaAs cleaved-edge overgrowth quantum wire to investigate adjacent quantum Hall edge states. We use the lowest five wire modes with their distinct wave functions to probe each edge state and apply magnetic fields to modify the wave functions and their overlap. This reveals an intricate and rich tunneling conductance fan structure which is succinctly different for each of the wire modes. We self-consistently solve the Poisson-Schrödinger equations to simulate the spectroscopy, reproducing the striking fans in great detail, thus, confirming the calculations. Further, the model predicts hybridization between wire states and Landau levels, which is also confirmed experimentally. This establishes momentum-conserving tunneling spectroscopy as a powerful technique to probe edge state wave functions.
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Affiliation(s)
- T Patlatiuk
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - C P Scheller
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - D Hill
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Y Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - J C Egues
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
| | - G Barak
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - A Yacoby
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - L N Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - K W West
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - D M Zumbühl
- Departement Physik, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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5
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Volk C, Chatterjee A, Ansaloni F, Marcus CM, Kuemmeth F. Fast Charge Sensing of Si/SiGe Quantum Dots via a High-Frequency Accumulation Gate. NANO LETTERS 2019; 19:5628-5633. [PMID: 31339321 DOI: 10.1021/acs.nanolett.9b02149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Quantum dot arrays are a versatile platform for the implementation of spin qubits, as high-bandwidth sensor dots can be integrated with single-, double-, and triple-dot qubits yielding fast and high-fidelity qubit readout. However, for undoped silicon devices, reflectometry off sensor ohmics suffers from the finite resistivity of the two-dimensional electron gas (2DEG), and alternative readout methods are limited to measuring qubit capacitance, rather than qubit charge. By coupling a surface-mount resonant circuit to the plunger gate of a high-impedance sensor, we realized a fast charge sensing technique that is compatible with resistive 2DEGs. We demonstrate this by acquiring at high speed charge stability diagrams of double- and triple-dot arrays in Si/SiGe heterostructures as well as pulsed-gate single-shot charge and spin readout with integration times as low as 2.4 μs.
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Affiliation(s)
- Christian Volk
- Center for Quantum Devices, Niels Bohr Institute , University of Copenhagen and Microsoft Quantum Lab Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
| | - Anasua Chatterjee
- Center for Quantum Devices, Niels Bohr Institute , University of Copenhagen and Microsoft Quantum Lab Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
| | - Fabio Ansaloni
- Center for Quantum Devices, Niels Bohr Institute , University of Copenhagen and Microsoft Quantum Lab Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute , University of Copenhagen and Microsoft Quantum Lab Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
| | - Ferdinand Kuemmeth
- Center for Quantum Devices, Niels Bohr Institute , University of Copenhagen and Microsoft Quantum Lab Copenhagen , Universitetsparken 5 , 2100 Copenhagen , Denmark
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6
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Camenzind LC, Yu L, Stano P, Zimmerman JD, Gossard AC, Loss D, Zumbühl DM. Spectroscopy of Quantum Dot Orbitals with In-Plane Magnetic Fields. PHYSICAL REVIEW LETTERS 2019; 122:207701. [PMID: 31172765 DOI: 10.1103/physrevlett.122.207701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 02/05/2019] [Indexed: 06/09/2023]
Abstract
We show that in-plane magnetic-field-assisted spectroscopy allows extraction of the in-plane orientation and full 3D size parameters of the quantum mechanical orbitals of a single electron GaAs lateral quantum dot with subnanometer precision. The method is based on measuring the orbital energies in a magnetic field with various strengths and orientations in the plane of the 2D electron gas. From such data, we deduce the microscopic confinement potential landscape and quantify the degree by which it differs from a harmonic oscillator potential. The spectroscopy is used to validate shape manipulation with gate voltages, agreeing with expectations from the gate layout. Our measurements demonstrate a versatile tool for quantum dots with one dominant axis of strong confinement.
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Affiliation(s)
- Leon C Camenzind
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Liuqi Yu
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Peter Stano
- Center for Emergent Matter Science, RIKEN, Saitama 351-0198, Japan
- Department of Applied Physics, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Institute of Physics, Slovak Academy of Sciences, 845 11 Bratislava, Slovakia
| | - Jeramy D Zimmerman
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Arthur C Gossard
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
- Center for Emergent Matter Science, RIKEN, Saitama 351-0198, Japan
| | - Dominik M Zumbühl
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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7
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Camenzind LC, Yu L, Stano P, Zimmerman JD, Gossard AC, Loss D, Zumbühl DM. Hyperfine-phonon spin relaxation in a single-electron GaAs quantum dot. Nat Commun 2018; 9:3454. [PMID: 30150721 PMCID: PMC6110844 DOI: 10.1038/s41467-018-05879-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/30/2018] [Indexed: 12/05/2022] Open
Abstract
Understanding and control of the spin relaxation time T1 is among the key challenges for spin-based qubits. A larger T1 is generally favored, setting the fundamental upper limit to the qubit coherence and spin readout fidelity. In GaAs quantum dots at low temperatures and high in-plane magnetic fields B, the spin relaxation relies on phonon emission and spin-orbit coupling. The characteristic dependence T1 ∝ B-5 and pronounced B-field anisotropy were already confirmed experimentally. However, it has also been predicted 15 years ago that at low enough fields, the spin-orbit interaction is replaced by the coupling to the nuclear spins, where the relaxation becomes isotropic, and the scaling changes to T1 ∝ B-3. Here, we establish these predictions experimentally, by measuring T1 over an unprecedented range of magnetic fields-made possible by lower temperature-and report a maximum T1 = 57 ± 15 s at the lowest fields, setting a record electron spin lifetime in a nanostructure.
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Affiliation(s)
- Leon C Camenzind
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Liuqi Yu
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Peter Stano
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan
- Department of Applied Physics, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Institute of Physics, Slovak Academy of Sciences, 845 11, Bratislava, Slovakia
| | - Jeramy D Zimmerman
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
- Physics Department, Colorado School of Mines, Golden, CO, 80401, USA
| | - Arthur C Gossard
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
- Center for Emergent Matter Science, RIKEN, Saitama, 351-0198, Japan
| | - Dominik M Zumbühl
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
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8
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Otsuka T, Nakajima T, Delbecq MR, Amaha S, Yoneda J, Takeda K, Allison G, Stano P, Noiri A, Ito T, Loss D, Ludwig A, Wieck AD, Tarucha S. Higher-order spin and charge dynamics in a quantum dot-lead hybrid system. Sci Rep 2017; 7:12201. [PMID: 28939803 PMCID: PMC5610234 DOI: 10.1038/s41598-017-12217-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/05/2017] [Indexed: 11/09/2022] Open
Abstract
Understanding the dynamics of open quantum systems is important and challenging in basic physics and applications for quantum devices and quantum computing. Semiconductor quantum dots offer a good platform to explore the physics of open quantum systems because we can tune parameters including the coupling to the environment or leads. Here, we apply the fast single-shot measurement techniques from spin qubit experiments to explore the spin and charge dynamics due to tunnel coupling to a lead in a quantum dot-lead hybrid system. We experimentally observe both spin and charge time evolution via first- and second-order tunneling processes, and reveal the dynamics of the spin-flip through the intermediate state. These results enable and stimulate the exploration of spin dynamics in dot-lead hybrid systems, and may offer useful resources for spin manipulation and simulation of open quantum systems.
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Affiliation(s)
- Tomohiro Otsuka
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. .,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan. .,JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
| | - Takashi Nakajima
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Matthieu R Delbecq
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Shinichi Amaha
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Jun Yoneda
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Kenta Takeda
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Giles Allison
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Peter Stano
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Institute of Physics, Slovak Academy of Sciences, 845 11, Bratislava, Slovakia
| | - Akito Noiri
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Takumi Ito
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Daniel Loss
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Department of Physics, University of Basel, Klingelbergstrasse 82, 4056, Basel, Switzerland
| | - Arne Ludwig
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Andreas D Wieck
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780, Bochum, Germany
| | - Seigo Tarucha
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. .,Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan. .,Quantum-Phase Electronics Center, University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan. .,Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, 153-8505, Japan.
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