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Yin P, Chen S, Radovanovic PV. Properties of Free Charge Carriers Govern Exciton Polarization in Plasmonic Semiconductor Nanocrystals. J Phys Chem Lett 2022; 13:5545-5552. [PMID: 35695871 DOI: 10.1021/acs.jpclett.2c00857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Interaction between a plasmon, as a collective property of charge carriers, and electronic or spin states in complex nanostructures has emerged as one of the fascinating topics that intertwines the fields of photonics, optoelectronics, and spintronics. Here, we investigate the magneto-optical properties of plasmonic InN and Cu2-xSe nanocrystals and show that the complete exciton polarization induced by cyclotron motion of free carriers is a universal phenomenon in semiconductor nanocrystals. The selective exciton polarization is governed by the angular momentum transfer from the carriers following cyclotron orbits to the excited electronic band states and can be controlled by carrier type (electrons or holes), mass, and velocity. The results of this work demonstrate the free-carrier-induced control of the states around the Fermi level and the exciton polarization in technologically important III-V nanocrystals, allowing for new ways of tailoring quantum states for spintronic and optoelectronic applications.
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Affiliation(s)
- Penghui Yin
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Shuoyuan Chen
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Pavle V Radovanovic
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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2
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Shilina PV, Ignatyeva DO, Kapralov PO, Sekatskii SK, Nur-E-Alam M, Vasiliev M, Alameh K, Achanta VG, Song Y, Hamidi SM, Zvezdin AK, Belotelov VI. Nanophotonic structures with optical surface modes for tunable spin current generation. NANOSCALE 2021; 13:5791-5799. [PMID: 33704301 DOI: 10.1039/d0nr08692d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We propose a novel type of photonic-crystal (PC)-based nanostructures for efficient and tunable optically-induced spin current generation via the spin Seebeck and inverse spin Hall effects. It has been experimentally demonstrated that optical surface modes localized at the PC surface covered by ferromagnetic layer and materials with giant spin-orbit coupling (SOC) notably increase the efficiency of the optically-induced spin current generation, and provides its tunability by modifying the light wavelength or angle of incidence. Up to 100% of the incident light power can be transferred to heat within the SOC layer and, therefore, to the spin current. Importantly, the high efficiency becomes accessible even for ultra-thin SOC layers. Moreover, the surface patterning of the PC-based spintronic nanostructure allows for the local generation of spin currents at the pattern scales rather than the diameter of the laser beam.
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Affiliation(s)
- P V Shilina
- National Research University Higher School of Economics, Moscow 101000, Russia.
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3
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Pappas SD, Lang P, Eul T, Hartelt M, García-Martín A, Hillebrands B, Aeschlimann M, Papaioannou ET. Near-field mechanism of the enhanced broadband magneto-optical activity of hybrid Au loaded Bi:YIG. NANOSCALE 2020; 12:7309-7314. [PMID: 32202292 DOI: 10.1039/d0nr00198h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We unravel the underlying near-field mechanism of the enhancement of the magneto-optical activity of bismuth-substituted yttrium iron garnet films (Bi:YIG) loaded with gold nanoparticles. The experimental results show that the embedded gold nanoparticles lead to a broadband enhancement of the magneto-optical activity with respect to the activity of the bare Bi:YIG films. Full vectorial near- and far-field simulations demonstrate that this broadband enhancement is the result of a magneto-optically enabled cross-talking of orthogonal localized plasmon resonances. Our results pave the way to the on-demand design of the magneto-optical properties of hybrid magneto-plasmonic circuitry.
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Affiliation(s)
- Spiridon D Pappas
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
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4
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Huang P, Zhang P, Xu S, Wang H, Zhang X, Zhang H. Recent advances in two-dimensional ferromagnetism: materials synthesis, physical properties and device applications. NANOSCALE 2020; 12:2309-2327. [PMID: 31930261 DOI: 10.1039/c9nr08890c] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two-dimensional (2D) ferromagnetism is critical for both scientific investigation and technological development owing to its low-dimensionality that brings in quantization of electronic states as well as free axes for device modulation. However, the scarcity of high-temperature 2D ferromagnets has been the obstacle of many research studies, such as the quantum anomalous Hall effect (QAHE) and thin-film spintronics. Indeed, in the case of the isotropic Heisenberg model with finite-range exchange interactions as an example, low-dimensionality is shown to be contraindicated with ferromagnetism. However, the advantages of low-dimensionality for micro-scale patterning could enhance the Curie temperature (TC) of 2D ferromagnets beyond the TC of bulk materials, opening the door for designing high-temperature ferromagnets in the 2D limit. In this paper, we review the recent advances in the field of 2D ferromagnets, including their material systems, physical properties, and potential device applications.
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Affiliation(s)
- Pu Huang
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Peng Zhang
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Shaogang Xu
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Huide Wang
- Collaborative Innovation Centre for Optoelectronic Science & Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Xiuwen Zhang
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Han Zhang
- Collaborative Innovation Centre for Optoelectronic Science & Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
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5
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Yin P, Hegde M, Tan Y, Chen S, Garnet N, Radovanovic PV. Controlling the Mechanism of Excitonic Splitting in In 2O 3 Nanocrystals by Carrier Delocalization. ACS NANO 2018; 12:11211-11218. [PMID: 30335948 DOI: 10.1021/acsnano.8b05782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Degenerately doped metal oxide nanocrystals have emerged as infrared plasmonic materials with promising applications in optoelectronics, surface-enhanced infrared spectroscopies, and sensing. They also have potential for technological applications in electronics and photonics owing to the possibility of coupling between plasmon and exciton in the absence of a heterojunction. Here, we demonstrate the control of excitonic splitting in In2O3 nanocrystals upon excitation with circularly polarized light in an external magnetic field by simultaneous control of the electronic structure of donor defects and the nanocrystal host lattice. Using variable-temperature-variable-field magnetic circular dichroism spectroscopy, we show that the nanocrystal band splitting has two distinct contributions in plasmonic In2O3 nanocrystals. Temperature-independent splitting arises from the cyclotron magnetoplasmonic modes, which impart angular momentum to the conduction band excited states near the Fermi level, and increases with the intensity of the corresponding plasmon resonance. Temperature-dependent splitting is associated with the localized electron spins trapped in defect states. The ratio of the two components can be controlled by the formation of oxygen vacancies or introduction of aliovalent dopants. Using these experimental results in conjunction with the density functional theory modeling, relative contribution of the two mechanisms is discussed in the context of the perturbation theory taking into account energy separation between the nanocrystal excited states and the localized defect states. The results of this work demonstrate the ability to control carrier polarization in nonmagnetic metal oxide nanocrystals using both individual and collective electronic properties and allow for their application as an emerging class of multifunctional materials with strongly interacting degrees of freedom.
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Affiliation(s)
- Penghui Yin
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
| | - Manu Hegde
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
| | - Yi Tan
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
| | - Shuoyuan Chen
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
| | - Natalie Garnet
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
| | - Pavle V Radovanovic
- Department of Chemistry , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2L 3G1 , Canada
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6
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Kapaklis V. Magnetizing semiconductors with light. NATURE NANOTECHNOLOGY 2018; 13:438-439. [PMID: 29686290 DOI: 10.1038/s41565-018-0119-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Vassilios Kapaklis
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
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7
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Yin P, Tan Y, Fang H, Hegde M, Radovanovic PV. Plasmon-induced carrier polarization in semiconductor nanocrystals. NATURE NANOTECHNOLOGY 2018; 13:463-467. [PMID: 29686293 DOI: 10.1038/s41565-018-0096-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Spintronics 1 and valleytronics 2 are emerging quantum electronic technologies that rely on using electron spin and multiple extrema of the band structure (valleys), respectively, as additional degrees of freedom. There are also collective properties of electrons in semiconductor nanostructures that potentially could be exploited in multifunctional quantum devices. Specifically, plasmonic semiconductor nanocrystals3-10 offer an opportunity for interface-free coupling between a plasmon and an exciton. However, plasmon-exciton coupling in single-phase semiconductor nanocrystals remains challenging because confined plasmon oscillations are generally not resonant with excitonic transitions. Here, we demonstrate a robust electron polarization in degenerately doped In2O3 nanocrystals, enabled by non-resonant coupling of cyclotron magnetoplasmonic modes 11 with the exciton at the Fermi level. Using magnetic circular dichroism spectroscopy, we show that intrinsic plasmon-exciton coupling allows for the indirect excitation of the magnetoplasmonic modes, and subsequent Zeeman splitting of the excitonic states. Splitting of the band states and selective carrier polarization can be manipulated further by spin-orbit coupling. Our results effectively open up the field of plasmontronics, which involves the phenomena that arise from intrinsic plasmon-exciton and plasmon-spin interactions. Furthermore, the dynamic control of carrier polarization is readily achieved at room temperature, which allows us to harness the magnetoplasmonic mode as a new degree of freedom in practical photonic, optoelectronic and quantum-information processing devices.
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Affiliation(s)
- Penghui Yin
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | - Yi Tan
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | - Hanbing Fang
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
| | - Manu Hegde
- Department of Chemistry, University of Waterloo, Waterloo, ON, Canada
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Lavrentiev V, Chvostova D, Stupakov A, Lavrentieva I, Vacik J, Motylenko M, Barchuk M, Rafaja D, Dejneka A. Quantum plasmon and Rashba-like spin splitting in self-assembled Co x C 60 composites with enhanced Co content (x > 15). NANOTECHNOLOGY 2018; 29:135701. [PMID: 29368694 DOI: 10.1088/1361-6528/aaaa7a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Driving by interplay between plasmonic and magnetic effects in organic composite semiconductors is a challenging task with a huge potential for practical applications. Here, we present evidence of a quantum plasmon excited in the self-assembled Co x C60 nanocomposite films with x > 15 (interval of the Co cluster coalescence) and analyse it using the optical absorption (OA) spectra. In the case of Co x C60 film with x = 16 (LF sample), the quantum plasmon generated by the Co/CoO clusters is found as the 1.5 eV-centred OA peak. This finding is supported by the establishment of four specific C60-related OA lines detected at the photon energies E p > 2.5 eV. Increase of the Co content up to x = 29 (HF sample) leads to pronounced enhancement of OA intensity in the energy range of E p > 2.5 eV and to plasmonic peak downshift of 0.2 eV with respect to the peak position in the LF spectrum. Four pairs of the OA peaks evaluated in the HF spectrum at E p > 2.5 eV reflect splitting of the C60-related lines, suggesting great change in the microscopic conditions with increasing x. Analysis of the film nanostructure and the plasmon-induced conditions allows us to propose a Rashba-like spin splitting effect that suggests valuable sources for spin polarization.
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Affiliation(s)
- Vasily Lavrentiev
- Nuclear Physics Institute of the Czech Academy of Sciences, Rez-130, Husinec 25068, Czechia
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9
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Chen YJ, Zakeri K, Ernst A, Qin HJ, Meng Y, Kirschner J. Group Velocity Engineering of Confined Ultrafast Magnons. PHYSICAL REVIEW LETTERS 2017; 119:267201. [PMID: 29328716 DOI: 10.1103/physrevlett.119.267201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Indexed: 06/07/2023]
Abstract
Quantum confinement permits the existence of multiple terahertz magnon modes in atomically engineered ultrathin magnetic films and multilayers. By means of spin-polarized high-resolution electron energy-loss spectroscopy, we report on the direct experimental detection of all exchange-dominated terahertz confined magnon modes in a 3 ML Co film. We demonstrate that, by tuning the structural and magnetic properties of the Co film, through its epitaxial growth on different surfaces, e.g., Ir(001), Cu(001), and Pt(111), one can achieve entirely different in-plane magnon dispersions, characterized by positive and negative group velocities. Our first-principles calculations show that spin-dependent many-body correlation effects in Co films play an important role in the determination of the energies of confined magnon modes. Our results suggest a pathway towards the engineering of the group velocity of confined ultrafast magnons.
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Affiliation(s)
- Y-J Chen
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
| | - Kh Zakeri
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
- Heisenberg Spin-dynamics Group, Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Strasse 1, D-76131 Karlsruhe, Germany
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
- Institute for Theroretical Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - H J Qin
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
| | - Y Meng
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Von-Seckendorff-Platz 1, 06120 Halle, Germany
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10
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Wheeler MC, Ma'Mari FA, Rogers M, Gonçalves FJ, Moorsom T, Brataas A, Stamps R, Ali M, Burnell G, Hickey BJ, Cespedes O. Optical conversion of pure spin currents in hybrid molecular devices. Nat Commun 2017; 8:926. [PMID: 29030558 PMCID: PMC5640639 DOI: 10.1038/s41467-017-01034-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 08/14/2017] [Indexed: 11/20/2022] Open
Abstract
Carbon-based molecules offer unparalleled potential for THz and optical devices controlled by pure spin currents: a low-dissipation flow of electronic spins with no net charge displacement. However, the research so far has been focused on the electrical conversion of the spin imbalance, where molecular materials are used to mimic their crystalline counterparts. Here, we use spin currents to access the molecular dynamics and optical properties of a fullerene layer. The spin mixing conductance across Py/C60 interfaces is increased by 10% (5 × 1018 m-2) under optical irradiation. Measurements show up to a 30% higher light absorbance and a factor of 2 larger photoemission during spin pumping. We also observe a 0.15 THz slowdown and a narrowing of the vibrational peaks. The effects are attributed to changes in the non-radiative damping and energy transfer. This opens new research paths in hybrid magneto-molecular optoelectronics, and the optical detection of spin physics in these materials.Carbon-based molecules could prove useful in terahertz and optical devices controlled by pure spin currents. Here, conversely, the authors use spin currents to probe molecular dynamics and enhance the optical response of a fullerene layer, enabling hybrid magneto-molecular optoelectronic devices.
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Affiliation(s)
- May C Wheeler
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Fatma Al Ma'Mari
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Physics, Sultan Qaboos University, PO Box 36, Muscat, 123, Oman
| | - Matthew Rogers
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | | | - Timothy Moorsom
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Arne Brataas
- Department of Physics, Norwegian University of Science and Technology, Trondheim, NO, 7491, Norway
| | - Robert Stamps
- School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Mannan Ali
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Gavin Burnell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - B J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
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11
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Tunable Magneto-Optical Kerr Effects of Nanoporous Thin Films. Sci Rep 2017; 7:2888. [PMID: 28588241 PMCID: PMC5460283 DOI: 10.1038/s41598-017-03241-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/20/2017] [Indexed: 11/09/2022] Open
Abstract
Magnetoplasmonics, combining magnetic and plasmonic functions, has attracted increasing attention owing to its unique magnetic and optical properties in various nano-architectures. In this work, Ag, CoFeB and ITO layers are fabricated on anodic aluminum oxide (AAO) porous films to form hybrid multi-layered nanoporous thin films by magnetron sputtering deposition process. The designed nanostructure supports localized surface plasmon resonance (LSPR) and tunable magneto-optical (MO) activity, namely, the sign inversion, which can be controlled by AAO porous film geometry (pore diameter and inter-pore spacing) flexibly. The physical mechanism of this special MO phenomena is further analyzed and discussed by the correlation of Kerr rotation and electronic oscillations controlled by the surface plasmon resonance that is related to the nanoporous structure.
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12
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Sato M, Takayoshi S, Oka T. Laser-Driven Multiferroics and Ultrafast Spin Current Generation. PHYSICAL REVIEW LETTERS 2016; 117:147202. [PMID: 27740836 DOI: 10.1103/physrevlett.117.147202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 06/06/2023]
Abstract
We propose an ultrafast way to generate spin chirality and spin current in a class of multiferroic magnets using a terahertz circularly polarized laser. Using the Floquet formalism for periodically driven systems, we show that it is possible to dynamically control the Dzyaloshinskii-Moriya interaction in materials with magnetoelectric coupling. This is supported by numerical calculations, by which additional resonant phenomena are found. Specifically, when a static magnetic field is applied in addition to the circularly polarized laser, a large resonant enhancement of spin chirality is observed resembling the electron spin resonance. Spin current is generated when the laser is spatially modulated by chiral plasmonic structures and could be detected using optospintronic devices.
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Affiliation(s)
- Masahiro Sato
- Department of Physics, Ibaraki University, Mito, Ibaraki 310-8512, Japan
- Department of Physics and Mathematics, Aoyama-Gakuin University, Sagamihara, Kanagawa 229-8558, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
- ERATO, Japan Science and Technology Agency, Sendai, Miyagi 980-8577, Japan
| | - Shintaro Takayoshi
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, Geneva 1211, Switzerland
| | - Takashi Oka
- Max-Planck-Institut für Physik komplexer Systeme (MPI-PKS), Nöthnitzer Straße 38, Dresden 01187, Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe (MPI-CPfS), Nöthnitzer Straße 40, Dresden 01187, Germany
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13
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Kanazawa N, Goto T, Sekiguchi K, Granovsky AB, Ross CA, Takagi H, Nakamura Y, Inoue M. Demonstration of a robust magnonic spin wave interferometer. Sci Rep 2016; 6:30268. [PMID: 27443989 PMCID: PMC4957262 DOI: 10.1038/srep30268] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/17/2016] [Indexed: 11/23/2022] Open
Abstract
Magnonics is an emerging field dealing with ultralow power consumption logic circuits, in which the flow of spin waves, rather than electric charges, transmits and processes information. Waves, including spin waves, excel at encoding information via their phase using interference. This enables a number of inputs to be processed in one device, which offers the promise of multi-input multi-output logic gates. To realize such an integrated device, it is essential to demonstrate spin wave interferometers using spatially isotropic spin waves with high operational stability. However, spin wave reflection at the waveguide edge has previously limited the stability of interfering waves, precluding the use of isotropic spin waves, i.e., forward volume waves. Here, a spin wave absorber is demonstrated comprising a yttrium iron garnet waveguide partially covered by gold. This device is shown experimentally to be a robust spin wave interferometer using the forward volume mode, with a large ON/OFF isolation value of 13.7 dB even in magnetic fields over 30 Oe.
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Affiliation(s)
- Naoki Kanazawa
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580, Japan
| | - Taichi Goto
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580, Japan.,JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Koji Sekiguchi
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.,Department of Physics, Keio University, Yokohama 223-8522, Japan
| | | | - Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Hiroyuki Takagi
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580, Japan
| | - Yuichi Nakamura
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580, Japan
| | - Mitsuteru Inoue
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580, Japan
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14
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Verhagen TGA, Tinkey HN, Overweg HC, van Son M, Huber M, van Ruitenbeek JM, Aarts J. Temperature dependence of spin pumping and Gilbert damping in thin Co/Pt bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:056004. [PMID: 26759959 DOI: 10.1088/0953-8984/28/5/056004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on the temperature dependence of the spin-pumping effect and the Gilbert damping in Co/Pt bilayers grown on Silicon oxide by measuring the change of the linewidth in a ferromagnetic resonance (FMR) experiment. By varying the Co thickness d(Co) between 1.5 nm and 50 nm we find that the damping increases inversely proportional to d(Co) at all temperatures between 300 K and 5 K, showing that the spin pumping effect does not depend on temperature. We also find that the linewidth increases with decreasing temperature for all thicknesses down to about 30 K, before leveling off to a constant, or even decreasing again. This behavior is similar to what is found in bulk ferromagnets, leading to the conclusion that in thin films a conductivity-like damping mechanism is present similar to what is known in crystals.
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Affiliation(s)
- T G A Verhagen
- Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, PO Box 9504, 2300 RA Leiden, The Netherlands
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