1
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Dodson JP, Ercan HE, Corrigan J, Losert MP, Holman N, McJunkin T, Edge LF, Friesen M, Coppersmith SN, Eriksson MA. How Valley-Orbit States in Silicon Quantum Dots Probe Quantum Well Interfaces. Phys Rev Lett 2022; 128:146802. [PMID: 35476478 DOI: 10.1103/physrevlett.128.146802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 12/24/2021] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
The energies of valley-orbit states in silicon quantum dots are determined by an as yet poorly understood interplay between interface roughness, orbital confinement, and electron interactions. Here, we report measurements of one- and two-electron valley-orbit state energies as the dot potential is modified by changing gate voltages, and we calculate these same energies using full configuration interaction calculations. The results enable an understanding of the interplay between the physical contributions and enable a new probe of the quantum well interface.
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Affiliation(s)
- J P Dodson
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - H Ekmel Ercan
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Corrigan
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Merritt P Losert
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Nathan Holman
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Thomas McJunkin
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L F Edge
- HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, California 90265, USA
| | - Mark Friesen
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S N Coppersmith
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- University of New South Wales, Sydney, New South Wales 2052, Australia
| | - M A Eriksson
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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2
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Hu RZ, Ma RL, Ni M, Zhang X, Zhou Y, Wang K, Luo G, Cao G, Kong ZZ, Wang GL, Li HO, Guo GP. An Operation Guide of Si-MOS Quantum Dots for Spin Qubits. Nanomaterials (Basel) 2021; 11:2486. [PMID: 34684927 PMCID: PMC8540968 DOI: 10.3390/nano11102486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/13/2021] [Accepted: 09/18/2021] [Indexed: 11/23/2022]
Abstract
In the last 20 years, silicon quantum dots have received considerable attention from academic and industrial communities for research on readout, manipulation, storage, near-neighbor and long-range coupling of spin qubits. In this paper, we introduce how to realize a single spin qubit from Si-MOS quantum dots. First, we introduce the structure of a typical Si-MOS quantum dot and the experimental setup. Then, we show the basic properties of the quantum dot, including charge stability diagram, orbital state, valley state, lever arm, electron temperature, tunneling rate and spin lifetime. After that, we introduce the two most commonly used methods for spin-to-charge conversion, i.e., Elzerman readout and Pauli spin blockade readout. Finally, we discuss the details of how to find the resonance frequency of spin qubits and show the result of coherent manipulation, i.e., Rabi oscillation. The above processes constitute an operation guide for helping the followers enter the field of spin qubits in Si-MOS quantum dots.
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Affiliation(s)
- Rui-Zi Hu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Rong-Long Ma
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ming Ni
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xin Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yuan Zhou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ke Wang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gang Luo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhen-Zhen Kong
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China;
| | - Gui-Lei Wang
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China;
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China; (R.-Z.H.); (R.-L.M.); (M.N.); (X.Z.); (Y.Z.); (K.W.); (G.L.); (G.C.); (G.-P.G.)
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Origin Quantum Computing Company Limited, Hefei 230026, China
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3
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Kato K, Liu Y, Murakami S, Morita Y, Mori T. Electron beam lithography with negative tone resist for highly integrated silicon quantum bits. Nanotechnology 2021; 32:485301. [PMID: 34425562 DOI: 10.1088/1361-6528/ac201b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Process technologies have been developed for electron-beam (EB) lithography aimed at silicon quantum devices and their large-scale integration. It is necessary to understand the proximity effect and construct a method for its correction to perform EB lithography of fine and complicated structures. In this study, we investigate the lithography of Si quantum devices with a point-beam EB system and a maN 2401 negative tone resist, in order to correspond to various types of device structures. We optimize temperatures for specialized pre- and post-exposure bakes for forming ∼20 nm fine patterns with small line-edge roughness. Further, we demonstrated the fabrication of Si-on-insulator device patterns that have some tiny dots connected with many large wires/pads in the layout, with the careful tuning of the dose assignment. In this tuning, we used the EB process simulation to estimate the cumulative dose distribution effectively. In addition, we reproduced the experimentally obtained resist patterns via the EB process simulation after considering the mid-range effect, which is a factors in the proximity effect but is not yet deeply understood. The results of this study are expected to provide useful process technologies for EB lithography, which will help drastically accelerate the research on Si quantum devices with a high degree of freedom.
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Affiliation(s)
- Kimihiko Kato
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Yongxun Liu
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Shigenori Murakami
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Yukinori Morita
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Takahiro Mori
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568, Japan
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4
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Zhang X, Hu RZ, Li HO, Jing FM, Zhou Y, Ma RL, Ni M, Luo G, Cao G, Wang GL, Hu X, Jiang HW, Guo GC, Guo GP. Giant Anisotropy of Spin Relaxation and Spin-Valley Mixing in a Silicon Quantum Dot. Phys Rev Lett 2020; 124:257701. [PMID: 32639759 DOI: 10.1103/physrevlett.124.257701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/20/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
In silicon quantum dots (QDs), at a certain magnetic field commonly referred to as the "hot spot," the electron spin relaxation rate (T_{1}^{-1}) can be drastically enhanced due to strong spin-valley mixing. Here, we experimentally find that with a valley splitting of 78.2±1.6 μeV, this hot spot in spin relaxation can be suppressed by more than 2 orders of magnitude when the in-plane magnetic field is oriented at an optimal angle, about 9° from the [100] sample plane. This directional anisotropy exhibits a sinusoidal modulation with a 180° periodicity. We explain the magnitude and phase of this modulation using a model that accounts for both spin-valley mixing and intravalley spin-orbit mixing. The generality of this phenomenon is also confirmed by tuning the electric field and the valley splitting up to 268.5±0.7 μeV.
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Affiliation(s)
- Xin Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Rui-Zi Hu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fang-Ming Jing
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuan Zhou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Rong-Long Ma
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ming Ni
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Luo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gui-Lei Wang
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, USA
| | - Hong-Wen Jiang
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Guang-Can Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Origin Quantum Computing Company Limited, Hefei, Anhui 230026, China
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5
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Russ M, Péterfalvi CG, Burkard G. Theory of valley-resolved spectroscopy of a Si triple quantum dot coupled to a microwave resonator. J Phys Condens Matter 2020; 32:165301. [PMID: 31829981 DOI: 10.1088/1361-648x/ab613f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We theoretically study a silicon triple quantum dot (TQD) system coupled to a superconducting microwave resonator. The response signal of an injected probe signal can be used to extract information about the level structure by measuring the transmission and phase shift of the output field. This information can further be used to gain knowledge about the valley splittings and valley phases in the individual dots. Since relevant valley states are typically split by several [Formula: see text], a finite temperature or an applied external bias voltage is required to populate energetically excited states. The theoretical methods in this paper include a capacitor model to fit experimental charging energies, an extended Hubbard model to describe the tunneling dynamics, a rate equation model to find the occupation probabilities, and an input-output model to determine the response signal of the resonator.
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6
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Leon RCC, Yang CH, Hwang JCC, Lemyre JC, Tanttu T, Huang W, Chan KW, Tan KY, Hudson FE, Itoh KM, Morello A, Laucht A, Pioro-Ladrière M, Saraiva A, Dzurak AS. Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot. Nat Commun 2020; 11:797. [PMID: 32047151 PMCID: PMC7012832 DOI: 10.1038/s41467-019-14053-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/11/2019] [Indexed: 11/09/2022] Open
Abstract
Once the periodic properties of elements were unveiled, chemical behaviour could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in semiconductor materials disrupt this analogy, so real devices seldom display a systematic many-electron arrangement. We demonstrate here an electrostatically confined quantum dot that reveals a well defined shell structure. We observe four shells (31 electrons) with multiplicities given by spin and valley degrees of freedom. Various fillings containing a single valence electron-namely 1, 5, 13 and 25 electrons-are found to be potential qubits. An integrated micromagnet allows us to perform electrically-driven spin resonance (EDSR), leading to faster Rabi rotations and higher fidelity single qubit gates at higher shell states. We investigate the impact of orbital excitations on single qubits as a function of the dot deformation and exploit it for faster qubit control.
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Affiliation(s)
- R C C Leon
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
- Research and Prototype Foundry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - J Camirand Lemyre
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
| | - T Tanttu
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - W Huang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K W Chan
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Y Tan
- QCD Labs COMP Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - M Pioro-Ladrière
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
- Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, M5G 1Z8, Canada
| | - A Saraiva
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - A 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.
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7
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Kurzmann A, Eich M, Overweg H, Mangold M, Herman F, Rickhaus P, Pisoni R, Lee Y, Garreis R, Tong C, Watanabe K, Taniguchi T, Ensslin K, Ihn T. Excited States in Bilayer Graphene Quantum Dots. Phys Rev Lett 2019; 123:026803. [PMID: 31386494 DOI: 10.1103/physrevlett.123.026803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 05/21/2023]
Abstract
We report ground- and excited-state transport through an electrostatically defined few-hole quantum dot in bilayer graphene in both parallel and perpendicular applied magnetic fields. A remarkably clear level scheme for the two-particle spectra is found by analyzing finite bias spectroscopy data within a two-particle model including spin and valley degrees of freedom. We identify the two-hole ground state to be a spin-triplet and valley-singlet state. This spin alignment can be seen as Hund's rule for a valley-degenerate system, which is fundamentally different from quantum dots in carbon nanotubes, where the two-particle ground state is a spin-singlet state. The spin-singlet excited states are found to be valley-triplet states by tilting the magnetic field with respect to the sample plane. We quantify the exchange energy to be 0.35 meV and measure a valley and spin g factor of 36 and 2, respectively.
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Affiliation(s)
- A Kurzmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Eich
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - H Overweg
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Mangold
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - F Herman
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - P Rickhaus
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - R Pisoni
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Y Lee
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - R Garreis
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Tong
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - K Ensslin
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
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8
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Betz AC, Wacquez R, Vinet M, Jehl X, Saraiva AL, Sanquer M, Ferguson AJ, Gonzalez-Zalba MF. Dispersively Detected Pauli Spin-Blockade in a Silicon Nanowire Field-Effect Transistor. Nano Lett 2015; 15:4622-4627. [PMID: 26047255 DOI: 10.1021/acs.nanolett.5b01306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the dispersive readout of the spin state of a double quantum dot formed at the corner states of a silicon nanowire field-effect transistor. Two face-to-face top-gate electrodes allow us to independently tune the charge occupation of the quantum dot system down to the few-electron limit. We measure the charge stability of the double quantum dot in DC transport as well as dispersively via in situ gate-based radio frequency reflectometry, where one top-gate electrode is connected to a resonator. The latter removes the need for external charge sensors in quantum computing architectures and provides a compact way to readout the dispersive shift caused by changes in the quantum capacitance during inter-dot charge transitions. Here, we observe Pauli spin-blockade in the high-frequency response of the circuit at finite magnetic fields between singlet and triplet states. The blockade is lifted at higher magnetic fields when intra-dot triplet states become the ground state configuration. A line shape analysis of the dispersive phase shift reveals furthermore an intra-dot valley-orbit splitting Δvo of 145 μeV. Our results open up the possibility to operate compact complementary metal-oxide semiconductor (CMOS) technology as a singlet-triplet qubit and make split-gate silicon nanowire architectures an ideal candidate for the study of spin dynamics.
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Affiliation(s)
- A C Betz
- †Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - R Wacquez
- ‡CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble, France
| | - M Vinet
- ‡CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble, France
| | - X Jehl
- §SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - A L Saraiva
- ∥Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, Brazil
| | - M Sanquer
- §SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - A J Ferguson
- ⊥Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - M F Gonzalez-Zalba
- †Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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9
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Abstract
The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over the valley state opens new possibilities for quantum information processing. Combining qubits encoded in the singlet-triplet subspace of spin and valley states allows for universal QC using a universal two-qubit gate directly provided by the exchange interaction. We show how spin and valley qubits can be separated in order to allow for single-qubit rotations.
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Affiliation(s)
- Niklas Rohling
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Maximilian Russ
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Guido Burkard
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
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10
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Weber B, Tan YHM, Mahapatra S, Watson TF, Ryu H, Rahman R, Hollenberg LCL, Klimeck G, Simmons MY. Spin blockade and exchange in Coulomb-confined silicon double quantum dots. Nat Nanotechnol 2014; 9:430-435. [PMID: 24727686 DOI: 10.1038/nnano.2014.63] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 02/26/2014] [Indexed: 06/03/2023]
Abstract
Electron spins confined to phosphorus donors in silicon are promising candidates as qubits because of their long coherence times, exceeding seconds in isotopically purified bulk silicon. With the recent demonstrations of initialization, readout and coherent manipulation of individual donor electron spins, the next challenge towards the realization of a Si:P donor-based quantum computer is the demonstration of exchange coupling in two tunnel-coupled phosphorus donors. Spin-to-charge conversion via Pauli spin blockade, an essential ingredient for reading out individual spin states, is challenging in donor-based systems due to the inherently large donor charging energies (∼45 meV), requiring large electric fields (>1 MV m(-1)) to transfer both electron spins onto the same donor. Here, in a carefully characterized double donor-dot device, we directly observe spin blockade of the first few electrons and measure the effective exchange interaction between electron spins in coupled Coulomb-confined systems.
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Affiliation(s)
- Bent Weber
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Y H Matthias Tan
- Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - Suddhasatta Mahapatra
- 1] Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia [2]
| | - Thomas F Watson
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Hoon Ryu
- National Institute of Supercomputing and Networking, Korea Institute of Science and Technology Information, 245 Daehak-ro, Yuseong-gu, Daejeon 305-806, South Korea
| | - Rajib Rahman
- Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - Lloyd C L Hollenberg
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Gerhard Klimeck
- Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, Indiana 47907, USA
| | - Michelle Y Simmons
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
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11
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Voisin B, Nguyen VH, Renard J, Jehl X, Barraud S, Triozon F, Vinet M, Duchemin I, Niquet YM, de Franceschi S, Sanquer M. Few-electron edge-state quantum dots in a silicon nanowire field-effect transistor. Nano Lett 2014; 14:2094-2098. [PMID: 24611581 DOI: 10.1021/nl500299h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigate the gate-induced onset of few-electron regime through the undoped channel of a silicon nanowire field-effect transistor. By combining low-temperature transport measurements and self-consistent calculations, we reveal the formation of one-dimensional conduction modes localized at the two upper edges of the channel. Charge traps in the gate dielectric cause electron localization along these edge modes, creating elongated quantum dots with characteristic lengths of ∼10 nm. We observe single-electron tunneling across two such dots in parallel, specifically one in each channel edge. We identify the filling of these quantum dots with the first few electrons, measuring addition energies of a few tens of millielectron volts and level spacings of the order of 1 meV, which we ascribe to the valley orbit splitting. The total removal of valley degeneracy leaves only a 2-fold spin degeneracy, making edge quantum dots potentially promising candidates for silicon spin qubits.
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Affiliation(s)
- Benoit Voisin
- SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC , 17 rue des Martyrs, 38054 Grenoble, France
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12
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Yang CH, Rossi A, Ruskov R, Lai NS, Mohiyaddin FA, Lee S, Tahan C, Klimeck G, Morello A, Dzurak AS. Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting. Nat Commun 2013; 4. [DOI: 10.1038/ncomms3069] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 05/27/2013] [Indexed: 12/12/2022] Open
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13
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Roche B, Dupont-Ferrier E, Voisin B, Cobian M, Jehl X, Wacquez R, Vinet M, Niquet YM, Sanquer M. Detection of a large valley-orbit splitting in silicon with two-donor spectroscopy. Phys Rev Lett 2012; 108:206812. [PMID: 23003174 DOI: 10.1103/physrevlett.108.206812] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Indexed: 06/01/2023]
Abstract
We measure a large valley-orbit splitting for shallow isolated phosphorus donors in a silicon gated nanowire. This splitting is close to the bulk value and well above previous reports in silicon nanostructures. It was determined using a double dopant transport spectroscopy which eliminates artifacts induced by the environment. Quantitative simulations taking into account the position of the donors with respect to the Si/SiO2 interface and electric field in the wire show that the values found are consistent with the device geometry.
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Affiliation(s)
- B Roche
- SPSMS, UMR-E CEA / UJF-Grenoble 1, INAC, 17 rue des Martyrs, 38054 Grenoble, France
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14
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Culcer D, Saraiva AL, Koiller B, Hu X, Das Sarma S. Valley-based noise-resistant quantum computation using Si quantum dots. Phys Rev Lett 2012; 108:126804. [PMID: 22540611 DOI: 10.1103/physrevlett.108.126804] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Indexed: 05/31/2023]
Abstract
We devise a platform for noise-resistant quantum computing using the valley degree of freedom of Si quantum dots. The qubit is encoded in two polarized (1,1) spin-triplet states with different valley compositions in a double quantum dot, with a Zeeman field enabling unambiguous initialization. A top gate gives a difference in the valley splitting between the dots, allowing controllable interdot tunneling between opposite valley eigenstates, which enables one-qubit rotations. Two-qubit operations rely on a stripline resonator, and readout on charge sensing. Sensitivity to charge and spin fluctuations is determined by intervalley processes and is greatly reduced as compared to conventional spin and charge qubits. We describe a valley echo for further noise suppression.
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Affiliation(s)
- Dimitrie Culcer
- ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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