1
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Murzakhanov FF, Sadovnikova MA, Gracheva IN, Mamin GV, Baibekov EI, Mokhov EN. Exploring the properties of theVB-defect in hBN: optical spin polarization, Rabi oscillations, and coherent nuclei modulation. NANOTECHNOLOGY 2024; 35:155001. [PMID: 38154127 DOI: 10.1088/1361-6528/ad1940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/27/2023] [Indexed: 12/30/2023]
Abstract
Optically active point defects in semiconductors have received great attention in the field of solid-state quantum technologies. Hexagonal boron nitride, with an ultra-wide band gapEg= 6 eV, containing a negatively charged boron vacancy (VB-) with unique spin, optical, and coherent properties presents a new two-dimensional platform for the implementation of quantum technologies. This work establishes the value ofVB-spin polarization under optical pumping withλext= 532 nm laser using high-frequency (νmw= 94 GHz) electron paramagnetic resonance (EPR) spectroscopy. In optimal conditions polarization was found to beP≈ 38.4%. Our study reveals that Rabi oscillations induced on polarized spin states persist for up to 30-40μs, which is nearly two orders of magnitude longer than what was previously reported. Analysis of the coherent electron-nuclear interaction through the observed electron spin echo envelope modulation made it possible to detect signals from remote nitrogen and boron nuclei, and to establish a corresponding quadrupole coupling constantCq= 180 kHz related to nuclear quadrupole moment of14N. These results have fundamental importance for understanding the spin properties of boron vacancy.
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Affiliation(s)
- Fadis F Murzakhanov
- Institute of Physics, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Russia
| | | | - Irina N Gracheva
- Institute of Physics, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Russia
| | - Georgy V Mamin
- Institute of Physics, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Russia
| | - Eduard I Baibekov
- Institute of Physics, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Russia
| | - Evgeniy N Mokhov
- Ioffe Institute, Polytekhnicheskaya, 26, St Petersburg 194021, Russia
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2
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Cilibrizzi P, Arshad MJ, Tissot B, Son NT, Ivanov IG, Astner T, Koller P, Ghezellou M, Ul-Hassan J, White D, Bekker C, Burkard G, Trupke M, Bonato C. Ultra-narrow inhomogeneous spectral distribution of telecom-wavelength vanadium centres in isotopically-enriched silicon carbide. Nat Commun 2023; 14:8448. [PMID: 38114478 PMCID: PMC10730896 DOI: 10.1038/s41467-023-43923-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/23/2023] [Indexed: 12/21/2023] Open
Abstract
Spin-active quantum emitters have emerged as a leading platform for quantum technologies. However, one of their major limitations is the large spread in optical emission frequencies, which typically extends over tens of GHz. Here, we investigate single V4+ vanadium centres in 4H-SiC, which feature telecom-wavelength emission and a coherent S = 1/2 spin state. We perform spectroscopy on single emitters and report the observation of spin-dependent optical transitions, a key requirement for spin-photon interfaces. By engineering the isotopic composition of the SiC matrix, we reduce the inhomogeneous spectral distribution of different emitters down to 100 MHz, significantly smaller than any other single quantum emitter. Additionally, we tailor the dopant concentration to stabilise the telecom-wavelength V4+ charge state, thereby extending its lifetime by at least two orders of magnitude. These results bolster the prospects for single V emitters in SiC as material nodes in scalable telecom quantum networks.
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Affiliation(s)
- Pasquale Cilibrizzi
- School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Muhammad Junaid Arshad
- School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Benedikt Tissot
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - Nguyen Tien Son
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - Ivan G Ivanov
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - Thomas Astner
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, A-1090, Vienna, Austria
| | - Philipp Koller
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, A-1090, Vienna, Austria
| | - Misagh Ghezellou
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - Jawad Ul-Hassan
- Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - Daniel White
- School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Christiaan Bekker
- School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Guido Burkard
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - Michael Trupke
- Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, A-1090, Vienna, Austria.
| | - Cristian Bonato
- School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom.
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3
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Rizzato R, Schalk M, Mohr S, Hermann JC, Leibold JP, Bruckmaier F, Salvitti G, Qian C, Ji P, Astakhov GV, Kentsch U, Helm M, Stier AV, Finley JJ, Bucher DB. Extending the coherence of spin defects in hBN enables advanced qubit control and quantum sensing. Nat Commun 2023; 14:5089. [PMID: 37607945 PMCID: PMC10444786 DOI: 10.1038/s41467-023-40473-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 07/26/2023] [Indexed: 08/24/2023] Open
Abstract
Negatively-charged boron vacancy centers ([Formula: see text]) in hexagonal Boron Nitride (hBN) are attracting increasing interest since they represent optically-addressable qubits in a van der Waals material. In particular, these spin defects have shown promise as sensors for temperature, pressure, and static magnetic fields. However, their short spin coherence time limits their scope for quantum technology. Here, we apply dynamical decoupling techniques to suppress magnetic noise and extend the spin coherence time by two orders of magnitude, approaching the fundamental T1 relaxation limit. Based on this improvement, we demonstrate advanced spin control and a set of quantum sensing protocols to detect radiofrequency signals with sub-Hz resolution. The corresponding sensitivity is benchmarked against that of state-of-the-art NV-diamond quantum sensors. This work lays the foundation for nanoscale sensing using spin defects in an exfoliable material and opens a promising path to quantum sensors and quantum networks integrated into ultra-thin structures.
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Affiliation(s)
- Roberto Rizzato
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany.
- University of Bari, Department of Physics "M. Merlin", Via Amendola 173, Bari, 70125, Italy.
| | - Martin Schalk
- Walter Schottky Institute, TUM School of Natural Sciences, Am Coulombwall 4, Garching bei München, 85748, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, München, D-80799, Germany
| | - Stephan Mohr
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany
| | - Jens C Hermann
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, München, D-80799, Germany
| | - Joachim P Leibold
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Physics, James-Franck-Str. 1, Garching bei München, 85748, Germany
| | - Fleming Bruckmaier
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany
| | - Giovanna Salvitti
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany
- University of Bologna, Department of Chemistry "G. Ciamician", Via Selmi, 2, Bologna, 40126, Italy
| | - Chenjiang Qian
- Walter Schottky Institute, TUM School of Natural Sciences, Am Coulombwall 4, Garching bei München, 85748, Germany
| | - Peirui Ji
- Walter Schottky Institute, TUM School of Natural Sciences, Am Coulombwall 4, Garching bei München, 85748, Germany
| | - Georgy V Astakhov
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, Dresden, 01328, Germany
| | - Ulrich Kentsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, Dresden, 01328, Germany
| | - Manfred Helm
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, Dresden, 01328, Germany
- TU Dresden, 01062, Dresden, Germany
| | - Andreas V Stier
- Walter Schottky Institute, TUM School of Natural Sciences, Am Coulombwall 4, Garching bei München, 85748, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, München, D-80799, Germany
| | - Jonathan J Finley
- Walter Schottky Institute, TUM School of Natural Sciences, Am Coulombwall 4, Garching bei München, 85748, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, München, D-80799, Germany
| | - Dominik B Bucher
- Technical University of Munich, TUM School of Natural Sciences, Department of Chemistry, Lichtenbergstraße 4, Garching bei München, 85748, Germany.
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, München, D-80799, Germany.
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4
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Montblanch ARP, Barbone M, Aharonovich I, Atatüre M, Ferrari AC. Layered materials as a platform for quantum technologies. NATURE NANOTECHNOLOGY 2023:10.1038/s41565-023-01354-x. [PMID: 37322143 DOI: 10.1038/s41565-023-01354-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 02/17/2023] [Indexed: 06/17/2023]
Abstract
Layered materials are taking centre stage in the ever-increasing research effort to develop material platforms for quantum technologies. We are at the dawn of the era of layered quantum materials. Their optical, electronic, magnetic, thermal and mechanical properties make them attractive for most aspects of this global pursuit. Layered materials have already shown potential as scalable components, including quantum light sources, photon detectors and nanoscale sensors, and have enabled research of new phases of matter within the broader field of quantum simulations. In this Review we discuss opportunities and challenges faced by layered materials within the landscape of material platforms for quantum technologies. In particular, we focus on applications that rely on light-matter interfaces.
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Affiliation(s)
- Alejandro R-P Montblanch
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Matteo Barbone
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK
- Munich Center for Quantum Science and Technology, (MCQST), Munich, Germany
- Walter Schottky Institut and Department of Electrical and Computer Engineering, Technische Universität München, Garching, Germany
| | - Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
- Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
| | - Mete Atatüre
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK.
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5
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Coherence protection of spin qubits in hexagonal boron nitride. Nat Commun 2023; 14:461. [PMID: 36709208 PMCID: PMC9884286 DOI: 10.1038/s41467-023-36196-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 01/17/2023] [Indexed: 01/29/2023] Open
Abstract
Spin defects in foils of hexagonal boron nitride are an attractive platform for magnetic field imaging, since the probe can be placed in close proximity to the target. However, as a III-V material the electron spin coherence is limited by the nuclear spin environment, with spin echo coherence times of ∽100 ns at room temperature accessible magnetic fields. We use a strong continuous microwave drive with a modulation in order to stabilize a Rabi oscillation, extending the coherence time up to ∽ 4μs, which is close to the 10 μs electron spin lifetime in our sample. We then define a protected qubit basis, and show full control of the protected qubit. The coherence times of a superposition of the protected qubit can be as high as 0.8 μs. This work establishes that boron vacancies in hexagonal boron nitride can have electron spin coherence times that are competitive with typical nitrogen vacancy centres in small nanodiamonds under ambient conditions.
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6
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Aharonovich I, Tetienne JP, Toth M. Quantum Emitters in Hexagonal Boron Nitride. NANO LETTERS 2022; 22:9227-9235. [PMID: 36413674 DOI: 10.1021/acs.nanolett.2c03743] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Hexagonal boron nitride (hBN) has emerged as a fascinating platform to explore quantum emitters and their applications. Beyond being a wide-bandgap material, it is also a van der Waals crystal, enabling direct exfoliation of atomically thin layers─a combination which offers unique advantages over bulk, 3D crystals. In this Mini Review we discuss the unique properties of hBN quantum emitters and highlight progress toward their future implementation in practical devices. We focus on engineering and integration of the emitters with scalable photonic resonators. We also highlight recently discovered spin defects in hBN and discuss their potential utility for quantum sensing. All in all, hBN has become a front runner in explorations of solid-state quantum science with promising future prospects.
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Affiliation(s)
- Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
- ARC Centre of Excellence for Transformative Meta-Optical Systems, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | | | - Milos Toth
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
- ARC Centre of Excellence for Transformative Meta-Optical Systems, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
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7
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Curie D, Krogel JT, Cavar L, Solanki A, Upadhyaya P, Li T, Pai YY, Chilcote M, Iyer V, Puretzky A, Ivanov I, Du MH, Reboredo F, Lawrie B. Correlative Nanoscale Imaging of Strained hBN Spin Defects. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41361-41368. [PMID: 36048915 DOI: 10.1021/acsami.2c11886] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spin defects like the negatively charged boron vacancy color center (VB-) in hexagonal boron nitride (hBN) may enable new forms of quantum sensing with near-surface defects in layered van der Waals heterostructures. Here, the effect of strain on VB- color centers in hBN is revealed with correlative cathodoluminescence and photoluminescence microscopies. Strong localized enhancement and redshifting of the VB- luminescence is observed at creases, consistent with density functional theory calculations showing VB- migration toward regions with moderate uniaxial compressive strain. The ability to manipulate spin defects with highly localized strain is critical to the development of practical 2D quantum devices and quantum sensors.
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Affiliation(s)
- David Curie
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jaron T Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lukas Cavar
- Department of Physics, Indiana University, Bloomington, Indiana 47405, United States
| | - Abhishek Solanki
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Pramey Upadhyaya
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tongcang Li
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yun-Yi Pai
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Quantum Science Center, Oak Ridge, Tennessee 37831, United States
| | - Michael Chilcote
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Quantum Science Center, Oak Ridge, Tennessee 37831, United States
| | - Vasudevan Iyer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ilia Ivanov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Mao-Hua Du
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Fernando Reboredo
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Lawrie
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Quantum Science Center, Oak Ridge, Tennessee 37831, United States
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8
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Huang M, Zhou J, Chen D, Lu H, McLaughlin NJ, Li S, Alghamdi M, Djugba D, Shi J, Wang H, Du CR. Wide field imaging of van der Waals ferromagnet Fe3GeTe2 by spin defects in hexagonal boron nitride. Nat Commun 2022; 13:5369. [PMID: 36100604 PMCID: PMC9470674 DOI: 10.1038/s41467-022-33016-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 08/26/2022] [Indexed: 11/26/2022] Open
Abstract
Emergent color centers with accessible spins hosted by van der Waals materials have attracted substantial interest in recent years due to their significant potential for implementing transformative quantum sensing technologies. Hexagonal boron nitride (hBN) is naturally relevant in this context due to its remarkable ease of integration into devices consisting of low-dimensional materials. Taking advantage of boron vacancy spin defects in hBN, we report nanoscale quantum imaging of low-dimensional ferromagnetism sustained in Fe3GeTe2/hBN van der Waals heterostructures. Exploiting spin relaxometry methods, we have further observed spatially varying magnetic fluctuations in the exfoliated Fe3GeTe2 flake, whose magnitude reaches a peak value around the Curie temperature. Our results demonstrate the capability of spin defects in hBN of investigating local magnetic properties of layered materials in an accessible and precise way, which can be extended readily to a broad range of miniaturized van der Waals heterostructure systems. Hexagonal boron nitride (h-BN) has been used extensively to encapsulate other van der Waals materials, protecting them from environmental degradation, and allowing integration into more complex heterostructures. Here, the authors make use of boron vacancy spin defects in h-BN using them to image the magnetic properties of a Fe3GeTe2 flake.
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9
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Gao X, Vaidya S, Li K, Ju P, Jiang B, Xu Z, Allcca AEL, Shen K, Taniguchi T, Watanabe K, Bhave SA, Chen YP, Ping Y, Li T. Nuclear spin polarization and control in hexagonal boron nitride. NATURE MATERIALS 2022; 21:1024-1028. [PMID: 35970964 DOI: 10.1038/s41563-022-01329-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Electron spins in van der Waals materials are playing a crucial role in recent advances in condensed-matter physics and spintronics. However, nuclear spins in van der Waals materials remain an unexplored quantum resource. Here we report optical polarization and coherent control of nuclear spins in a van der Waals material at room temperature. We use negatively charged boron vacancy ([Formula: see text]) spin defects in hexagonal boron nitride to polarize nearby nitrogen nuclear spins. We observe the Rabi frequency of nuclear spins at the excited-state level anti-crossing of [Formula: see text] defects to be 350 times larger than that of an isolated nucleus, and demonstrate fast coherent control of nuclear spins. Further, we detect strong electron-mediated nuclear-nuclear spin coupling that is five orders of magnitude larger than the direct nuclear-spin dipolar coupling, enabling multi-qubit operations. Our work opens new avenues for the manipulation of nuclear spins in van der Waals materials for quantum information science and technology.
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Affiliation(s)
- Xingyu Gao
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - Sumukh Vaidya
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - Kejun Li
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Peng Ju
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - Boyang Jiang
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - Zhujing Xu
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | | | - Kunhong Shen
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Sunil A Bhave
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - Yong P Chen
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- WPI-AIMR International Research Center for Materials Sciences, Tohoku University, Sendai, Japan
| | - Yuan Ping
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Tongcang Li
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA.
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA.
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
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