1
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Wang F, Shi G, Yang D, Tan HR, Zhang C, Lei J, Pu Y, Yang S, Soumyanarayanan A, Elyasi M, Yang H. Deterministic switching of perpendicular magnetization by out-of-plane anti-damping magnon torques. NATURE NANOTECHNOLOGY 2024:10.1038/s41565-024-01741-y. [PMID: 39048707 DOI: 10.1038/s41565-024-01741-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 06/12/2024] [Indexed: 07/27/2024]
Abstract
Spin-wave excitations of magnetic moments (or magnons) can transport spin angular momentum in insulating magnetic materials. This property distinguishes magnonic devices from traditional electronics, where power consumption results from electrons' movement. Recently, magnon torques have been used to switch perpendicular magnetization in the presence of an external magnetic field. Here we present a material system composed of WTe2/antiferromagnetic insulator NiO/ferromagnet CoFeB heterostructures that allows magnetic field-free switching of the perpendicular magnetization. The magnon currents, with a spin polarization canting of -8.5° relative to the sample plane, traverse the 25-nm-thick polycrystalline NiO layer while preserving their original polarization direction, subsequently exerting an out-of-plane anti-damping magnon torque on the ferromagnetic layer. Using this mechanism, we achieve a 190-fold reduction in power consumption in PtTe2/WTe2/NiO/CoFeB heterostructures compared to Bi2Te3/NiO/CoFeB control samples, which only exhibit in-plane magnon torques. Our field-free demonstration contributes to the realization of all-electric, low-power, perpendicular magnetization switching devices.
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Affiliation(s)
- Fei Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and School of Chemistry and Materials Science, Shanxi Normal University, Taiyuan, China
| | - Guoyi Shi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Hui Ru Tan
- Institute of Materials Research and Engineering, Agency for Science, Technology & Research (A*STAR), Singapore, Singapore
| | - Chenhui Zhang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Jiayu Lei
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Yuchen Pu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shuhan Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Anjan Soumyanarayanan
- Institute of Materials Research and Engineering, Agency for Science, Technology & Research (A*STAR), Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Mehrdad Elyasi
- Advanced Institute for Materials Research, Tohoku University, Sendai, Japan.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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2
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Bobowski K, Zheng X, Frietsch B, Lawrenz D, Bronsch W, Gahl C, Andres B, Strüber C, Carley R, Teichmann M, Scherz A, Molodtsov S, Cacho C, Chapman RT, Springate E, Weinelt M. Ultrafast spin transfer and its impact on the electronic structure. SCIENCE ADVANCES 2024; 10:eadn4613. [PMID: 39018415 PMCID: PMC466954 DOI: 10.1126/sciadv.adn4613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 06/12/2024] [Indexed: 07/19/2024]
Abstract
Optically induced intersite spin transfer (OISTR) promises manipulation of spin systems within the ultimate time limit of laser excitation. Following its prediction, signatures of ultrafast spin transfer between oppositely aligned spin sublattices have been observed in magnetic alloys and multilayers. However, it is known neither from theory nor from experiment whether the band structure immediately follows the ultrafast change in spin polarization or whether the exchange split bands remain rigid. We show that ultrafast spin transfer occurs even in ferromagnetic gadolinium metal. Charge transfer between localized surface and extended valence-band states leads to a decrease of the surface spin polarization. This synchronously alters the exchange splitting of the bulk valence bands during laser excitation. Moreover, the onset of demagnetization can be tuned by over 200 fs by changing the temperature-dependent spin mixing. Our results show a promising route to ultrafast control of the magnetization, widening the impact and applicability of OISTR.
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Affiliation(s)
- Kamil Bobowski
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Xinwei Zheng
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Björn Frietsch
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Dominic Lawrenz
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Wibke Bronsch
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Cornelius Gahl
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Beatrice Andres
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Christian Strüber
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Robert Carley
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Andreas Scherz
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Serguei Molodtsov
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
- Institute of Experimental Physics, TU Bergakademie Freiberg, Leipziger Str. 23, 09599 Freiberg, Germany
| | | | | | | | - Martin Weinelt
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
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3
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Li S, Wang R, Frauenheim T, He J. Optical-Helicity-Dependent Orbital and Spin Dynamics in Two-Dimensional Ferromagnets. J Phys Chem Lett 2024; 15:5939-5946. [PMID: 38810216 PMCID: PMC11163468 DOI: 10.1021/acs.jpclett.4c01152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 05/31/2024]
Abstract
Disentangling orbital (OAM) and spin (SAM) angular momenta in the ultrafast spin dynamics of two-dimensional (2D) ferromagnets on subfemtoseconds is a challenge in the field of ultrafast magnetism. Herein, we employed a non-collinear spin version of real-time time-dependent density functional theory to investigate the orbital and spin dynamics of the 2D ferromagnets Fe3GeTe2 (FGT) induced by circularly polarized light. Our results show that the demagnetization of the Fe sublattice in FGT is accompanied by helicity-dependent precession of the OAM and SAM excited by circularly polarized lasers. We further identify that precession of the OAM and SAM in FGT is faster than demagnetization within a few femtoseconds. Remarkably, circularly polarized lasers can significantly induce a periodic transverse linear response of the OAM and SAM on very ultrafast time scales of ∼600 attoseconds. Our finding suggests a powerful new route for attosecond regimes of the angular momentum manipulation to coherently control helicity-dependent orbital and spin dynamics in 2D ferromagnets.
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Affiliation(s)
- Shuo Li
- Institute
for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Ran Wang
- Institute
for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Thomas Frauenheim
- Institute
for Advanced Study, Chengdu University, Chengdu 610106, China
- School
of Science, Constructor University, Bremen 28759, Germany
| | - Junjie He
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
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4
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Pantazopoulos PA, Feist J, García-Vidal FJ, Kamra A. Unconventional magnetism mediated by spin-phonon-photon coupling. Nat Commun 2024; 15:4000. [PMID: 38734667 PMCID: PMC11088681 DOI: 10.1038/s41467-024-48404-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
Magnetic order typically emerges due to the short-range exchange interaction between the constituent electronic spins. Recent discoveries have found a crucial role for spin-phonon coupling in various phenomena from optical ultrafast magnetization switching to dynamical control of the magnetic state. Here, we demonstrate theoretically the emergence of a biquadratic long-range interaction between spins mediated by their coupling to phonons hybridized with vacuum photons into polaritons. The resulting ordered state enabled by the exchange of virtual polaritons between spins is reminiscent of superconductivity mediated by the exchange of virtual phonons. The biquadratic nature of the spin-spin interaction promotes ordering without favoring ferro- or antiferromagnetism. It further makes the phase transition to magnetic order a first-order transition, unlike in conventional magnets. Consequently, a large magnetization develops abruptly on lowering the temperature which could enable magnetic memories admitting ultralow-power thermally-assisted writing while maintaining a high data stability. The role of photons in the phenomenon further enables an in-situ static control over the magnetism. These unique features make our predicted spin-spin interaction and magnetism highly unconventional paving the way for novel scientific and technological opportunities.
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Affiliation(s)
- Petros Andreas Pantazopoulos
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain.
| | - Johannes Feist
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain.
| | - Francisco J García-Vidal
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain.
| | - Akashdeep Kamra
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain.
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5
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Mitra S, Jiménez-Galán Á, Aulich M, Neuhaus M, Silva REF, Pervak V, Kling MF, Biswas S. Light-wave-controlled Haldane model in monolayer hexagonal boron nitride. Nature 2024; 628:752-757. [PMID: 38622268 PMCID: PMC11041748 DOI: 10.1038/s41586-024-07244-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 02/27/2024] [Indexed: 04/17/2024]
Abstract
In recent years, the stacking and twisting of atom-thin structures with matching crystal symmetry has provided a unique way to create new superlattice structures in which new properties emerge1,2. In parallel, control over the temporal characteristics of strong light fields has allowed researchers to manipulate coherent electron transport in such atom-thin structures on sublaser-cycle timescales3,4. Here we demonstrate a tailored light-wave-driven analogue to twisted layer stacking. Tailoring the spatial symmetry of the light waveform to that of the lattice of a hexagonal boron nitride monolayer and then twisting this waveform result in optical control of time-reversal symmetry breaking5 and the realization of the topological Haldane model6 in a laser-dressed two-dimensional insulating crystal. Further, the parameters of the effective Haldane-type Hamiltonian can be controlled by rotating the light waveform, thus enabling ultrafast switching between band structure configurations and allowing unprecedented control over the magnitude, location and curvature of the bandgap. This results in an asymmetric population between complementary quantum valleys that leads to a measurable valley Hall current7, which can be detected by optical harmonic polarimetry. The universality and robustness of our scheme paves the way to valley-selective bandgap engineering on the fly and unlocks the possibility of creating few-femtosecond switches with quantum degrees of freedom.
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Affiliation(s)
- Sambit Mitra
- Max Planck Institute of Quantum Optics, Garching, Germany
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany
| | - Álvaro Jiménez-Galán
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
- Max Born Institute, Berlin, Germany.
| | - Mario Aulich
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Marcel Neuhaus
- Max Planck Institute of Quantum Optics, Garching, Germany
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Rui E F Silva
- Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Volodymyr Pervak
- Max Planck Institute of Quantum Optics, Garching, Germany
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany
| | - Matthias F Kling
- Max Planck Institute of Quantum Optics, Garching, Germany
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Shubhadeep Biswas
- Max Planck Institute of Quantum Optics, Garching, Germany.
- Physics Department, Ludwig-Maximilian University of Munich, Garching, Germany.
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
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6
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Fang N, Wu C, Zhang Y, Li Z, Zhou Z. Perspectives: Light Control of Magnetism and Device Development. ACS NANO 2024; 18:8600-8625. [PMID: 38469753 DOI: 10.1021/acsnano.3c13002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Accurately controlling magnetic and spin states presents a significant challenge in spintronics, especially as demands for higher data storage density and increased processing speeds grow. Approaches such as light control are gradually supplanting traditional magnetic field methods. Traditionally, the modulation of magnetism was predominantly achieved through polarized light with the help of ultrafast light technologies. With the growing demand for energy efficiency and multifunctionality in spintronic devices, integrating photovoltaic materials into magnetoelectric systems has introduced more physical effects. This development suggests that sunlight will play an increasingly pivotal role in manipulating spin orientation in the future. This review introduces and concludes the influence of various light types on magnetism, exploring mechanisms such as magneto-optical (MO) effects, light-induced magnetic phase transitions, and spin photovoltaic effects. This review briefly summarizes recent advancements in the light control of magnetism, especially sunlight, and their potential applications, providing an optimistic perspective on future research directions in this area.
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Affiliation(s)
- Ning Fang
- School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
| | - Changqing Wu
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Yuzhe Zhang
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Zhongyu Li
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Ziyao Zhou
- School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
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7
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He J, Frauenheim T, Li S. Ultrafast Chiral Precession of Spin and Orbital Angular Momentum Induced by Circularly Polarized Laser Pulse in Elementary Ferromagnets. J Phys Chem Lett 2024; 15:2493-2498. [PMID: 38408454 PMCID: PMC10926150 DOI: 10.1021/acs.jpclett.4c00291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024]
Abstract
Despite spin (SAM) and orbital (OAM) angular momentum dynamics being well-studied in demagnetization processes, their components receive less focus. Here, we utilize real-time time-dependent density functional theory (rt-TDDFT) to unveil significant x and y components of SAM and OAM induced by circularly left (σ+) and right (σ-) polarized laser pulses in ferromagnetic Fe, Co, and Ni. Our results show that the magnitude of the OAM is an order of magnitude larger than that of the SAM, highlighting a stronger optical response from the orbital degrees of freedom of electrons. Intriguingly, σ+ and σ- pulses induce chirality in the precession of SAM and OAM, respectively, with clear associations with laser frequency and duration. Finally, we demonstrate the time scale of the OAM and SAM precession occurs even earlier than that of the demagnetization process and the OISTR effect. Our results provide detailed insight into the dynamics of SAM and OAM during and shortly after a polarized laser pulse.
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Affiliation(s)
- Junjie He
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
| | - Thomas Frauenheim
- Bremen
Center for Computational Materials Science, University of Bremen, Bremen 28359, Germany
| | - Shuo Li
- Institute
for Advanced Study, Chengdu University, Chengdu 610106, China
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8
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Neufeld O, Hübener H, Giovannini UD, Rubio A. Tracking electron motion within and outside of Floquet bands from attosecond pulse trains in time-resolved ARPES. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:225401. [PMID: 38364263 DOI: 10.1088/1361-648x/ad2a0e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/16/2024] [Indexed: 02/18/2024]
Abstract
Floquet engineering has recently emerged as a technique for controlling material properties with light. Floquet phases can be probed with time- and angle-resolved photoelectron spectroscopy (Tr-ARPES), providing direct access to the laser-dressed electronic bands. Applications of Tr-ARPES to date focused on observing the Floquet-Bloch bands themselves, and their build-up and dephasing on sub-laser-cycle timescales. However, momentum and energy resolved sub-laser-cycle dynamics between Floquet bands have not been analyzed. Given that Floquet theory strictly applies in time-periodic conditions, the notion of resolving sub-laser-cycle dynamics between Floquet states seems contradictory-it requires probe pulse durations below a laser cycle that inherently cannot discern the time-periodic nature of the light-matter system. Here we propose to employ attosecond pulse train probes with the same temporal periodicity as the Floquet-dressing pump pulse, allowing both attosecond sub-laser-cycle resolution and a proper projection of Tr-ARPES spectra on the Floquet-Bloch bands. We formulate and employ this approach inab-initiocalculations in light-driven graphene. Our calculations predict significant sub-laser-cycle dynamics occurring within the Floquet phase with the majority of electrons moving within and in-between Floquet bands, and a small portion residing and moving outside of them in what we denote as 'non-Floquet' bands. We establish that non-Floquet bands arise from the pump laser envelope that induces non-adiabatic electronic excitations during the pulse turn-on and turn-off. By performing calculations in systems with poly-chromatic pumps we also show that Floquet states are not formed on a sub-laser-cycle level. This work indicates that the Floquet-Bloch states are generally not a complete basis set for sub-laser-cycle dynamics in steady-state phases of matter.
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Affiliation(s)
- Ofer Neufeld
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-electron Laser Science, Hamburg 22761, Germany
| | - Hannes Hübener
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-electron Laser Science, Hamburg 22761, Germany
| | - Umberto De Giovannini
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-electron Laser Science, Hamburg 22761, Germany
- Università degli Studi di Palermo, Dipartimento di Fisica e Chimica-Emilio Segrè, Palermo I-90123, Italy
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-electron Laser Science, Hamburg 22761, Germany
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, New York, NY 10010, United States of America
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9
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Gajapathy H, Bandaranayake S, Hruska E, Vadakkayil A, Bloom BP, Londo S, McClellan J, Guo J, Russell D, de Groot FMF, Yang F, Waldeck DH, Schultze M, Baker LR. Spin polarized electron dynamics enhance water splitting efficiency by yttrium iron garnet photoanodes: a new platform for spin selective photocatalysis. Chem Sci 2024; 15:3300-3310. [PMID: 38425509 PMCID: PMC10901523 DOI: 10.1039/d3sc03016d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 01/16/2024] [Indexed: 03/02/2024] Open
Abstract
This work presents a spectroscopic and photocatalytic comparison of water splitting using yttrium iron garnet (Y3Fe5O12, YIG) and hematite (α-Fe2O3) photoanodes. Despite similar electronic structures, YIG significantly outperforms widely studied hematite, displaying more than an order of magnitude increase in photocurrent density. Probing the charge and spin dynamics by ultrafast, surface-sensitive XUV spectroscopy reveals that the enhanced performance arises from (1) reduced polaron formation in YIG compared to hematite and (2) an intrinsic spin polarization of catalytic photocurrents in YIG. Ultrafast XUV measurements show a reduction in the formation of surface electron polarons compared to hematite due to site-dependent electron-phonon coupling. This leads to spin polarized photocurrents in YIG where efficient charge separation occurs on the Td sub-lattice compared to fast trapping and electron/hole pair recombination on the Oh sub-lattice. These lattice-dependent dynamics result in a long-lived spin aligned hole population at the YIG surface, which is directly observed using XUV magnetic circular dichroism. Comparison of the Fe M2,3 and O L1-edges show that spin aligned holes are hybridized between O 2p and Fe 3d valence band states, and these holes are responsible for highly efficient, spin selective water oxidation by YIG. Together, these results point to YIG as a new platform for highly efficient, spin selective photocatalysis.
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Affiliation(s)
- Harshad Gajapathy
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Savini Bandaranayake
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Emily Hruska
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Aravind Vadakkayil
- Department of Chemistry, University of Pittsburgh 15260 Pittsburgh Pennsylvania USA
| | - Brian P Bloom
- Department of Chemistry, University of Pittsburgh 15260 Pittsburgh Pennsylvania USA
| | - Stephen Londo
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Jackson McClellan
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Jason Guo
- Department of Physics, The Ohio State University Columbus Ohio 43210 USA
| | - Daniel Russell
- Department of Physics, The Ohio State University Columbus Ohio 43210 USA
| | - Frank M F de Groot
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University 3584CG Utrecht The Netherlands
| | - Fengyuan Yang
- Department of Physics, The Ohio State University Columbus Ohio 43210 USA
| | - David H Waldeck
- Department of Chemistry, University of Pittsburgh 15260 Pittsburgh Pennsylvania USA
| | - Martin Schultze
- Institute of Experimental Physics, Graz University of Technology Petersgasse 16 Graz 8010 Austria
| | - L Robert Baker
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
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10
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Sharma S, Dewhurst JK, Shallcross S. Light-Shaping of Valley States. NANO LETTERS 2023; 23:11533-11539. [PMID: 38100087 DOI: 10.1021/acs.nanolett.3c03245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
The established paradigm to create valley states, excitations at local band extrema ("valleys"), is through selective occupation of specific valleys via circularly polarized laser pulses. Here we show a second way exists to create valley states, not by valley population imbalance but by "light-shaping" in momentum space, i.e. controlling the shape of the distribution of excited charge at each valley. While noncontrasting in valley charge, such valley states are instead characterized by a valley current, identically zero at one valley and finite and large at the other. We demonstrate that these (i) are robust to quantum decoherence, (ii) allow lossless toggling of the valley state with successive femtosecond laser pulses, and (iii) permit valley contrasting excitation both with and without a gap. Our findings open a route to robust ultrafast and switchable valleytronics in a wide scope of 2d materials, bringing closer the promise of valley-based electronics.
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Affiliation(s)
- Sangeeta Sharma
- Max-Born-Institute for Non-linear Optics and Short Pulse Spectroscopy, Max-Born Strasse 2A, 12489 Berlin, Germany
- Institute for theoretical solid-state physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - John Kay Dewhurst
- Max-Planck-Institut fur Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - Samuel Shallcross
- Max-Born-Institute for Non-linear Optics and Short Pulse Spectroscopy, Max-Born Strasse 2A, 12489 Berlin, Germany
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11
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Li M, He J. Terahertz Laser Pulse Boosts Interlayer Spin Transfer in Two-Dimensional van der Waals Magnetic Heterostructures. J Phys Chem Lett 2023; 14:11274-11280. [PMID: 38060526 PMCID: PMC10749471 DOI: 10.1021/acs.jpclett.3c03000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/22/2023]
Abstract
Light-induced ultrafast dynamics in two-dimensional (2D) magnetic systems demonstrate substantial advancements in spintronics. Here, using the real-time time-dependent density functional theory (rt-TDDFT), we applied laser pulses with various frequencies, from terahertz (THz) to optical pulse, to systematically study the interlayer spin transfer dynamics in 2D van der Waals nonmagnetic-ferromagnetic heterostructures, including graphene-Fe3GeTe2 (Gr/FGT) and silicene-Fe3GeTe2 (Si/FGT). Our results demonstrate that low-frequency THz pulses are particularly effective in facilitating interlayer spin injection from the ferromagnetic FGT layers to the Si or Gr layers. On the contrary, high-frequency optical pulses exhibit a minimal influence on this process. Such an effect is attributed to the low-frequency THz pulses inducing in-phase oscillations of the electron charge density around atomic centers, leading to a highly efficient interlayer spin transfer. Our results provide a new insight into ultrafast THz radiation control intralayer spin transfer and magnetic proximity dynamics in the 2D limit.
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Affiliation(s)
- Min Li
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
| | - Junjie He
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
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12
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Chen Z, Luo JW, Wang LW. Light-induced ultrafast spin transport in multilayer metallic films originates from sp- d spin exchange coupling. SCIENCE ADVANCES 2023; 9:eadi1618. [PMID: 38100591 PMCID: PMC10848703 DOI: 10.1126/sciadv.adi1618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 11/15/2023] [Indexed: 12/17/2023]
Abstract
Ultrafast interaction between the femtosecond laser pulse and the magnetic metal provides an efficient way to manipulate the magnetic states of matter. Numerous experimental advancements have been made on multilayer metallic films in the last two decades. However, the underlying physics remains unclear. Here, relying on an efficient ab initio spin dynamics simulation algorithm, we revealed the physics that can unify the progress in different experiments. We found that light-induced ultrafast spin transport in multilayer metallic films originates from the sp-d spin-exchange interaction, which can induce an ultrafast, large, and pure spin current from ferromagnetic metal to nonmagnetic metal without charge carrier transport. The resulting trends of spin demagnetization and spin flow are consistent with most experiments. It can explain a variety of ultrafast light-spin manipulation experiments with different systems and different pump-probe technologies, covering a wide range of work in this field.
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Affiliation(s)
- Zhanghui Chen
- Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
- Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 50F, Berkeley, CA 94720, USA
- University of Chinese Academy of Sciences, No.1 Yanqihu East Rd, Huairou District, Beijing 101408, China
| | - Jun-Wei Luo
- Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
- University of Chinese Academy of Sciences, No.1 Yanqihu East Rd, Huairou District, Beijing 101408, China
| | - Lin-Wang Wang
- Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
- Materials Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Mail Stop 50F, Berkeley, CA 94720, USA
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13
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de las Heras A, Bonafé FP, Hernández-García C, Rubio A, Neufeld O. Tunable Tesla-Scale Magnetic Attosecond Pulses through Ring-Current Gating. J Phys Chem Lett 2023; 14:11160-11167. [PMID: 38054653 PMCID: PMC10726360 DOI: 10.1021/acs.jpclett.3c02899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023]
Abstract
Coherent control over electron dynamics in atoms and molecules using high-intensity circularly polarized laser pulses gives rise to current loops, resulting in the emission of magnetic fields. We propose, and demonstrate with ab initio calculations, "current-gating" schemes to generate direct or alternating-current magnetic pulses in the infrared spectral region, with highly tunable waveform and frequency, and showing femtosecond-to-attosecond pulse duration. In optimal conditions, the magnetic pulse can be highly isolated from the driving laser and exhibits a high flux density (∼1 T at a few hundred nanometers from the source, with a pulse duration of 787 attoseconds) for application in forefront experiments of ultrafast spectroscopy. Our work paves the way toward the generation of attosecond magnetic fields to probe ultrafast magnetization, chiral responses, and spin dynamics.
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Affiliation(s)
- Alba de las Heras
- Grupo
de Investigación en Aplicaciones del Láser y Fotónica,
Departamento de Física Aplicada, Universidad de Salamanca, Salamanca 37008, Spain
| | - Franco P. Bonafé
- Max
Planck Institute for the Structure and Dynamics of Matter and Center
for Free-Electron Laser Science, Hamburg 22761, Germany
| | - Carlos Hernández-García
- Grupo
de Investigación en Aplicaciones del Láser y Fotónica,
Departamento de Física Aplicada, Universidad de Salamanca, Salamanca 37008, Spain
| | - Angel Rubio
- Max
Planck Institute for the Structure and Dynamics of Matter and Center
for Free-Electron Laser Science, Hamburg 22761, Germany
- Center
for Computational Quantum Physics, The Flatiron
Institute, New York 10010, United States
- Nano-Bio
Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco, San Sebastían 20018, Spain
| | - Ofer Neufeld
- Max
Planck Institute for the Structure and Dynamics of Matter and Center
for Free-Electron Laser Science, Hamburg 22761, Germany
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14
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Weiss MA, Herbst A, Schlegel J, Dannegger T, Evers M, Donges A, Nakajima M, Leitenstorfer A, Goennenwein STB, Nowak U, Kurihara T. Discovery of ultrafast spontaneous spin switching in an antiferromagnet by femtosecond noise correlation spectroscopy. Nat Commun 2023; 14:7651. [PMID: 38030606 PMCID: PMC10687256 DOI: 10.1038/s41467-023-43318-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 11/06/2023] [Indexed: 12/01/2023] Open
Abstract
Owing to their high magnon frequencies, antiferromagnets are key materials for future high-speed spintronics. Picosecond switching of antiferromagnetic spin systems has been viewed a milestone for decades and pursued only by using ultrafast external perturbations. Here, we show that picosecond spin switching occurs spontaneously due to thermal fluctuations in the antiferromagnetic orthoferrite Sm0.7Er0.3FeO3. By analysing the correlation between the pulse-to-pulse polarisation fluctuations of two femtosecond optical probes, we extract the autocorrelation of incoherent magnon fluctuations. We observe a strong enhancement of the magnon fluctuation amplitude and the coherence time around the critical temperature of the spin reorientation transition. The spectrum shows two distinct features, one corresponding to the quasi-ferromagnetic mode and another one which has not been previously reported in pump-probe experiments. Comparison to a stochastic spin dynamics simulation reveals this new mode as smoking gun of ultrafast spontaneous spin switching within the double-well anisotropy potential.
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Affiliation(s)
- M A Weiss
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - A Herbst
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - J Schlegel
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - T Dannegger
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - M Evers
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - A Donges
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - M Nakajima
- Institute of Laser Engineering, Osaka University, 565-0871, Osaka, Japan
| | - A Leitenstorfer
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - S T B Goennenwein
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - U Nowak
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany
| | - T Kurihara
- Department of Physics, University of Konstanz, D-78457, Konstanz, Germany.
- The Institute for Solid State Physics, The University of Tokyo, 277-8581, Kashiwa, Japan.
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15
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Ryan SA, Johnsen PC, Elhanoty MF, Grafov A, Li N, Delin A, Markou A, Lesne E, Felser C, Eriksson O, Kapteyn HC, Grånäs O, Murnane MM. Optically controlling the competition between spin flips and intersite spin transfer in a Heusler half-metal on sub-100-fs time scales. SCIENCE ADVANCES 2023; 9:eadi1428. [PMID: 37948525 PMCID: PMC10637748 DOI: 10.1126/sciadv.adi1428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during ultrafast laser excitation in magnetic alloys is challenging. Here, we study the Heusler compound Co2MnGa, a material that exhibits very strong light-induced spin transfers across the entire M-edge. By combining the element specificity of extreme ultraviolet high-harmonic probes with time-dependent density functional theory, we disentangle the competition between three ultrafast light-induced processes that occur in Co2MnGa: same-site Co-Co spin transfer, intersite Co-Mn spin transfer, and ultrafast spin flips mediated by spin-orbit coupling. By measuring the dynamic magnetic asymmetry across the entire M-edges of the two magnetic sublattices involved, we uncover the relative dominance of these processes at different probe energy regions and times during the laser pulse. Our combined approach enables a comprehensive microscopic interpretation of laser-induced magnetization dynamics on time scales shorter than 100 femtoseconds.
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Affiliation(s)
- Sinéad A. Ryan
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Peter C. Johnsen
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Mohamed F. Elhanoty
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
| | - Anya Grafov
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Na Li
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Anna Delin
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, SE-10691 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - Anastasios Markou
- Physics Department, University of Ioannina, 45110 Ioannina, Greece
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Edouard Lesne
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Olle Eriksson
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - Henry C. Kapteyn
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
- KMLabs Inc., Boulder, CO 80301, USA
| | - Oscar Grånäs
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
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16
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Li J, Li X, Yang J. Chemically Controlled Reversible Magnetic Phase Transition in Two-Dimensional Organometallic Lattices. NANO LETTERS 2023; 23:9126-9132. [PMID: 37781926 DOI: 10.1021/acs.nanolett.3c03060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Developing an efficient method to reversibly control materials' spin order is urgently needed but challenging in spintronics. Though various physical field control methods have been advancing, the chemical control of spin is little exploited. Here, we propose a chemical means for such spin manipulation, i.e., utilizing the well-known lactim-lactam tautomerization to reversibly modulate the magnetic phase transition in two-dimensional (2D) organometallic lattices. The proposal is verified by theoretically designing several 2D organometallic frameworks with antiferromagnetic to ferrimagnetic spin order transformation modulated by lactim-lactam tautomerization on organic linkers. The transition originates from the change in spin states of organic linkers (from singlet to doublet) via tautomerization. Such a transition further switches materials' electronic structures from normal semiconductors with zero spin polarization to bipolar magnetic semiconductors with valence and conduction band edges 100% spin polarized in opposite spin channels. Moreover, the magnitude of magnetic anisotropy energy also enhances by 5- to 9-fold.
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Affiliation(s)
- Junyao Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xingxing Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Jinlong Yang
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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17
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Anh LD, Kobayashi M, Takeda T, Araki K, Okano R, Sumi T, Horio M, Yamamoto K, Kubota Y, Owada S, Yabashi M, Matsuda I, Tanaka M. Ultrafast Subpicosecond Magnetization of a 2D Ferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2301347. [PMID: 37309900 DOI: 10.1002/adma.202301347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/12/2023] [Indexed: 06/14/2023]
Abstract
Strong spin-charge interactions in several ferromagnets are expected to lead to subpicosecond (sub-ps) magnetization of the magnetic materials through control of the carrier characteristics via electrical means, which is essential for ultrafast spin-based electronic devices. Thus far, ultrafast control of magnetization has been realized by optically pumping a large number of carriers into the d or f orbitals of a ferromagnet; however, it is extremely challenging to implement by electrical gating. This work demonstrates a new method for sub-ps magnetization manipulation called wavefunction engineering, in which only the spatial distribution (wavefunction) of s (or p) electrons is controlled and no change is required in the total carrier density. Using a ferromagnetic semiconductor (FMS) (In,Fe)As quantum well (QW), instant enhancement, as fast as 600 fs, of the magnetization is observed upon irradiating a femtosecond (fs) laser pulse. Theoretical analysis shows that the instant enhancement of the magnetization is induced when the 2D electron wavefunctions (WFs) in the FMS QW are rapidly moved by a photo-Dember electric field formed by an asymmetric distribution of the photocarriers. Because this WF engineering method can be equivalently implemented by applying a gate electric field, these results open a new way to realize ultrafast magnetic storage and spin-based information processing in present electronic systems.
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Affiliation(s)
- Le Duc Anh
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Saitama, Kawaguchi, 332-0012, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Masaki Kobayashi
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Takahito Takeda
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kohsei Araki
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Ryo Okano
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Toshihide Sumi
- Institute of Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8581, Japan
| | - Masafumi Horio
- Institute of Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8581, Japan
| | - Kohei Yamamoto
- Institute for Molecular Science, Okazaki, Aichi, 444-8585, Japan
| | - Yuya Kubota
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan
| | - Makina Yabashi
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan
| | - Iwao Matsuda
- Institute of Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8581, Japan
| | - Masaaki Tanaka
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- Institute for Nano Quantum Information Electronics (NanoQuine), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-0041, Japan
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18
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He J, Li S, Frauenheim T, Zhou Z. Ultrafast Laser Pulse Induced Transient Ferrimagnetic State and Spin Relaxation Dynamics in Two-Dimensional Antiferromagnets. NANO LETTERS 2023; 23:8348-8354. [PMID: 37642209 PMCID: PMC10510573 DOI: 10.1021/acs.nanolett.3c02727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/25/2023] [Indexed: 08/31/2023]
Abstract
We employ real-time time-dependent density functional theory (rt-TDDFT) and ab initio nonadiabatic molecular dynamics (NAMD) to systematically investigate the ultrafast laser pulses induced spin transfer and relaxation dynamics of two-dimensional (2D) antiferromagnetic-ferromagnetic (AFM/FM) MnPS3/MnSe2 van der Waals heterostructures. We demonstrate that laser pulses can induce a ferrimagnetic (FiM) state in the AFM MnPS3 layer within tens of femtoseconds and maintain it for subpicosecond time scale before reverting to the AFM state. We identify the mechanism in which the asymmetric optical intersite spin transfer (OISTR) effect occurring within the sublattices of the AFM and FM layers drives the interlayer spin-selective charge transfer, leading to the transition from AFM to FiM state. Furthermore, the unequal electron-phonon coupling of spin-up and spin-down channels of AFM spin sublattice causes an inequivalent spin relaxation, in turn extending the time scale of the FiM state. These findings are essential for designing novel optical-driven ultrafast 2D magnetic switches.
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Affiliation(s)
- Junjie He
- Faculty
of Science, Department of Physical and Macromolecular Chemistry, Charles University, Prague 12843, Czech Republic
| | - Shuo Li
- Institute
of Advanced Study, Chengdu University, Chengdu 610100, China
| | | | - Zhaobo Zhou
- Bremen
Center for Computational Materials Science, University of Bremen, Bremen 28359, Germany
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19
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Perosa G, Wätzel J, Garzella D, Allaria E, Bonanomi M, Danailov MB, Brynes A, Callegari C, De Ninno G, Demidovich A, Di Fraia M, Di Mitri S, Giannessi L, Manfredda M, Novinec L, Pal N, Penco G, Plekan O, Prince KC, Simoncig A, Spampinati S, Spezzani C, Zangrando M, Berakdar J, Feifel R, Squibb RJ, Coffee R, Hemsing E, Roussel E, Sansone G, McNeil BWJ, Ribič PR. Femtosecond Polarization Shaping of Free-Electron Laser Pulses. PHYSICAL REVIEW LETTERS 2023; 131:045001. [PMID: 37566861 DOI: 10.1103/physrevlett.131.045001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/13/2023] [Indexed: 08/13/2023]
Abstract
We demonstrate the generation of extreme-ultraviolet (XUV) free-electron laser (FEL) pulses with time-dependent polarization. To achieve polarization modulation on a femtosecond timescale, we combine two mutually delayed counterrotating circularly polarized subpulses from two cross-polarized undulators. The polarization profile of the pulses is probed by angle-resolved photoemission and above-threshold ionization of helium; the results agree with solutions of the time-dependent Schrödinger equation. The stability limit of the scheme is mainly set by electron-beam energy fluctuations, however, at a level that will not compromise experiments in the XUV. Our results demonstrate the potential to improve the resolution and element selectivity of methods based on polarization shaping and may lead to the development of new coherent control schemes for probing and manipulating core electrons in matter.
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Affiliation(s)
- Giovanni Perosa
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- Department of Physics, Università degli Studi di Trieste, 34127 Trieste, Italy
| | - Jonas Wätzel
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany
| | - David Garzella
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Enrico Allaria
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Matteo Bonanomi
- Politecnico di Milano, 20133 Milano, Italy
- Istituto di Fotonica e Nanotecnologie, 20133 Milano, Italy
| | | | | | - Carlo Callegari
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Giovanni De Ninno
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- Laboratory of Quantum Optics, University of Nova Gorica, 5001 Nova Gorica, Slovenia
| | | | - Michele Di Fraia
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, 34149 Basovizza, Italy
| | - Simone Di Mitri
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- Department of Physics, Università degli Studi di Trieste, 34127 Trieste, Italy
| | - Luca Giannessi
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- ENEA C.R. Frascati, 00044 Frascati (Roma), Italy
| | | | - Luka Novinec
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Nitish Pal
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Giuseppe Penco
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Oksana Plekan
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Kevin C Prince
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | | | | | - Carlo Spezzani
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Marco Zangrando
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
- Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, 34149 Basovizza, Italy
| | - Jamal Berakdar
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany
| | - Raimund Feifel
- Department of Physics, University of Gothenburg, 41133 Gothenburg, Sweden
| | - Richard J Squibb
- Department of Physics, University of Gothenburg, 41133 Gothenburg, Sweden
| | - Ryan Coffee
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Erik Hemsing
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Eléonore Roussel
- Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Giuseppe Sansone
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Brian W J McNeil
- University of Strathclyde (SUPA), Glasgow G4 0NG, United Kingdom
- Cockcroft Institute, Warrington WA4 4AD, United Kingdom
- ASTeC, STFC Daresbury Laboratory, Warrington WA4 4AD, United Kingdom
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20
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Zhou Z, Zheng Z, He J, Wang J, Prezhdo OV, Frauenheim T. Ultrafast Laser Control of Antiferromagnetic-Ferrimagnetic Switching in Two-Dimensional Ferromagnetic Semiconductor Heterostructures. NANO LETTERS 2023. [PMID: 37307217 DOI: 10.1021/acs.nanolett.3c01350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Realizing ultrafast control of magnetization switching is of crucial importance for information processing and recording technology. Here, we explore the laser-induced spin electron excitation and relaxation dynamics processes of CrCl3/CrBr3 heterostructures with antiparallel (AP) and parallel (P) systems. Although an ultrafast demagnetization of CrCl3 and CrBr3 layers occurs in both AP and P systems, the overall magnetic order of the heterostructure remains unchanged due to the laser-induced equivalent interlayer spin electron excitation. More crucially, the interlayer magnetic order switches from antiferromagnetic (AFM) to ferrimagnetic (FiM) in the AP system once the laser pulse disappears. The microscopic mechanism underpinning this magnetization switching is dominated by the asymmetrical interlayer charge transfer combined with a spin-flip, which breaks the interlayer AFM symmetry and ultimately results in an inequivalent shift in the moment between two FM layers. Our study opens up a new idea for ultrafast laser control of magnetization switching in two-dimensional opto-spintronic devices.
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Affiliation(s)
- Zhaobo Zhou
- Bremen Center for Computational Materials Science, University of Bremen, Bremen 28359, Germany
| | - Zhenfa Zheng
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Junjie He
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Prague 12843, Czech Republic
| | - Jinlan Wang
- School of Physics, Southeast University, Nanjing 211189, China
| | - Oleg V Prezhdo
- Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Thomas Frauenheim
- School of Science, Constructor University, Bremen 28759, Germany
- Beijing Computational Science Research Center, Beijing 100193, China
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen 518109, China
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21
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Mattern M, von Reppert A, Zeuschner SP, Herzog M, Pudell JE, Bargheer M. Concepts and use cases for picosecond ultrasonics with x-rays. PHOTOACOUSTICS 2023; 31:100503. [PMID: 37275326 PMCID: PMC10238750 DOI: 10.1016/j.pacs.2023.100503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/28/2023] [Accepted: 04/30/2023] [Indexed: 06/07/2023]
Abstract
This review discusses picosecond ultrasonics experiments using ultrashort hard x-ray probe pulses to extract the transient strain response of laser-excited nanoscopic structures from Bragg-peak shifts. This method provides direct, layer-specific, and quantitative information on the picosecond strain response for structures down to few-nm thickness. We model the transient strain using the elastic wave equation and express the driving stress using Grüneisen parameters stating that the laser-induced stress is proportional to energy density changes in the microscopic subsystems of the solid, i.e., electrons, phonons and spins. The laser-driven strain response can thus serve as an ultrafast proxy for local energy-density and temperature changes, but we emphasize the importance of the nanoscale morphology for an accurate interpretation due to the Poisson effect. The presented experimental use cases encompass ultrathin and opaque metal-heterostructures, continuous and granular nanolayers as well as negative thermal expansion materials, that each pose a challenge to established all-optical techniques.
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Affiliation(s)
- Maximilian Mattern
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
| | | | - Steffen Peer Zeuschner
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
- Helmholtz Zentrum Berlin, 12489 Berlin, Germany
| | - Marc Herzog
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
| | - Jan-Etienne Pudell
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
- Helmholtz Zentrum Berlin, 12489 Berlin, Germany
- European XFEL, 22869 Schenefeld, Germany
| | - Matias Bargheer
- Institut für Physik & Astronomie, Universität Potsdam, 14476 Potsdam, Germany
- Helmholtz Zentrum Berlin, 12489 Berlin, Germany
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22
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Reza Madhani A, Irani E, Monfared M. Generation of the isolated highly elliptically polarized attosecond pulse using the polarization gating technique: TDDFT approach. OPTICS EXPRESS 2023; 31:18430-18443. [PMID: 37381554 DOI: 10.1364/oe.488842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/08/2023] [Indexed: 06/30/2023]
Abstract
This paper theoretically investigates the generation of isolated elliptically polarized attosecond pulses with a tunable ellipticity from the interaction of Cl2 molecule and a polarization-gating laser pulse. A three-dimensional calculation based on the time-dependent density functional theory is done. Two different methods are proposed for generating elliptically polarized single attosecond pulses. The first method is based on applying a single-color polarization gating laser and controlling the orientation angle of the Cl2 molecule with respect to the polarization direction of the laser at the gate window. An attosecond pulse with an ellipticity of 0.66 and a pulse duration of 275 as is achieved by tuning the molecule orientation angle to 40° in this method and superposing harmonics around the harmonic cutoff. The second method is based on irradiating an aligned Cl2 molecule with a two-color polarization gating laser. The ellipticity of the attosecond pulses obtained by this method can be controlled by adjusting the intensity ratio of the two colors. Employing an optimized intensity ratio and superposing harmonics around the harmonic cutoff would lead to the generation of an isolated, highly elliptically polarized attosecond pulse with an ellipticity of 0.92 and a pulse duration of 648 as.
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23
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Liu B, Xiao H, Weinelt M. Microscopic insights to spin transport-driven ultrafast magnetization dynamics in a Gd/Fe bilayer. SCIENCE ADVANCES 2023; 9:eade0286. [PMID: 37196076 DOI: 10.1126/sciadv.ade0286] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 04/13/2023] [Indexed: 05/19/2023]
Abstract
Laser-induced spin transport is a key ingredient in ultrafast spin dynamics. However, it remains debated to what extent ultrafast magnetization dynamics generates spin currents and vice versa. We use time- and spin-resolved photoemission spectroscopy to study an antiferromagnetically coupled Gd/Fe bilayer, a prototype system for all-optical switching. Spin transport leads to an ultrafast drop of the spin polarization at the Gd surface, demonstrating angular-momentum transfer over several nanometers. Thereby, Fe acts as spin filter, absorbing spin majority but reflecting spin minority electrons. Spin transport from Gd to Fe was corroborated by an ultrafast increase of the Fe spin polarization in a reversed Fe/Gd bilayer. In contrast, for a pure Gd film, spin transport into the tungsten substrate can be neglected, as spin polarization stays constant. Our results suggest that ultrafast spin transport drives the magnetization dynamics in Gd/Fe and reveal microscopic insights into ultrafast spin dynamics.
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Affiliation(s)
- Bo Liu
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Huijuan Xiao
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Martin Weinelt
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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24
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Luttmann M, Vimal M, Guer M, Hergott JF, Khoury AZ, Hernández-García C, Pisanty E, Ruchon T. Nonlinear up-conversion of a polarization Möbius strip with half-integer optical angular momentum. SCIENCE ADVANCES 2023; 9:eadf3486. [PMID: 36961899 PMCID: PMC10038335 DOI: 10.1126/sciadv.adf3486] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Symmetries and conservation laws of energy, linear momentum, and angular momentum play a central role in nonlinear optics. Recently, paraxial light fields with nontrivial topology have been attracting a keen interest. Despite not being eigenstates of the orbital and spin angular momenta (OAM and SAM), they are eigenstates of the generalized angular momentum (GAM) operator-a mixture of the OAM and SAM operators with fractional eigenvalues. By driving high harmonic generation with a polarization Möbius strip carrying a half-integer GAM charge and implementing angular momentum characterization methods in the extreme ultraviolet range, we demonstrate the linear scaling of the GAM with the harmonic order, each harmonic carrying a precise half-integer GAM charge. Our work shows that beyond SAM and OAM, the GAM is, in some situations, an appropriate quantum number. It paves the way for finer manipulations and applications of light beams containing fractional-order polarization singularities.
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Affiliation(s)
- Martin Luttmann
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
| | - Mekha Vimal
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
| | - Matthieu Guer
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
- Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008, Spain
| | | | - Antonio Z. Khoury
- Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24210-346, Brazil
| | - Carlos Hernández-García
- Grupo de Investigación en Aplicaciones del Láser y Fotónica, Departamento de Física Aplicada, University of Salamanca, Salamanca E-37008, Spain
| | - Emilio Pisanty
- Department of Physics, King’s College London, Strand Campus, London WC2R 2LS, UK
| | - Thierry Ruchon
- Université Paris-Saclay, CEA, CNRS, LIDYL, Gif-sur-Yvette 91191, France
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25
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Johnsen PC, Ryan SA, Gentry C, Grafov A, Kapteyn H, Murnane M. A beamline for ultrafast extreme ultraviolet magneto-optical spectroscopy in reflection near the shot noise limit. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:033001. [PMID: 37012828 DOI: 10.1063/5.0127119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/30/2023] [Indexed: 06/19/2023]
Abstract
High harmonic generation (HHG) makes it possible to measure spin and charge dynamics in materials on femtosecond to attosecond timescales. However, the extreme nonlinear nature of the high harmonic process means that intensity fluctuations can limit measurement sensitivity. Here we present a noise-canceled, tabletop high harmonic beamline for time-resolved reflection mode spectroscopy of magnetic materials. We use a reference spectrometer to independently normalize the intensity fluctuations of each harmonic order and eliminate long term drift, allowing us to make spectroscopic measurements near the shot noise limit. These improvements allow us to significantly reduce the integration time required for high signal-to-noise (SNR) measurements of element-specific spin dynamics. Looking forward, improvements in the HHG flux, optical coatings, and grating design can further reduce the acquisition time for high SNR measurements by 1-2 orders of magnitude, enabling dramatically improved sensitivity to spin, charge, and phonon dynamics in magnetic materials.
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Affiliation(s)
- Peter C Johnsen
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Sinéad A Ryan
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Anya Grafov
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Henry Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Margaret Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
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26
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Zinchenko KS, Ardana-Lamas F, Lanfaloni VU, Luu TT, Pertot Y, Huppert M, Wörner HJ. Apparatus for attosecond transient-absorption spectroscopy in the water-window soft-X-ray region. Sci Rep 2023; 13:3059. [PMID: 36810355 PMCID: PMC9944907 DOI: 10.1038/s41598-023-29089-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/30/2023] [Indexed: 02/24/2023] Open
Abstract
We present an apparatus for attosecond transient-absorption spectroscopy (ATAS) featuring soft-X-ray (SXR) supercontinua that extend beyond 450 eV. This instrument combines an attosecond table-top high-harmonic light source with mid-infrared (mid-IR) pulses, both driven by 1.7-1.9 mJ, sub-11 fs pulses centered at 1.76 [Formula: see text]m. A remarkably low timing jitter of [Formula: see text] 20 as is achieved through active stabilization of the pump and probe arms of the instrument. A temporal resolution of better than 400 as is demonstrated through ATAS measurements at the argon L[Formula: see text]-edges. A spectral resolving power of 1490 is demonstrated through simultaneous absorption measurements at the sulfur L[Formula: see text]- and carbon K-edges of OCS. Coupled with its high SXR photon flux, this instrument paves the way to attosecond time-resolved spectroscopy of organic molecules in the gas phase or in aqueous solutions, as well as thin films of advanced materials. Such measurements will advance the studies of complex systems to the electronic time scale.
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Affiliation(s)
- Kristina S. Zinchenko
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
| | - Fernando Ardana-Lamas
- Laboratory of Physical Chemistry, ETH Zürich, 8093, Zurich, Switzerland. .,European XFEL GmbH, 22869, Schenefeld, Germany.
| | - Valentina Utrio Lanfaloni
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
| | - Tran Trung Luu
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland ,grid.194645.b0000000121742757Department of Physics, The University of Hong Kong, Pokfulam Road, SAR Hong Kong, People’s Republic of China
| | - Yoann Pertot
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
| | - Martin Huppert
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland ,grid.5991.40000 0001 1090 7501Paul Scherrer Institut, PSI, 5232 Villigen, Switzerland
| | - Hans Jakob Wörner
- grid.5801.c0000 0001 2156 2780Laboratory of Physical Chemistry, ETH Zürich, 8093 Zurich, Switzerland
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Ziolkowski F, Busch O, Mertig I, Henk J. Ultrafast spin dynamics: complementing theoretical analyses by quantum state measures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:125501. [PMID: 36652715 DOI: 10.1088/1361-648x/acb479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
In theoretical analyses of ultrafast spin dynamics simulated phenomena are commonly discussed in terms of observables. In this paper we report on possible benefits of complementing such studies by quantum state (QS) measures. These measures quantify specific properties of QSs, e.g. distance in Hilbert space and mixing. For Co/Cu heterostructures illuminated by femtosecond laser pulses, we discuss the general behavior of selected measures, but address in particular the degree of perturbation by a laser pulse. It turns out that the measures are especially sensitive to variations of the polarization of a laser pulse and the sample composition. Moreover, they are closely linked to magnetization and number of photo-excited electrons.
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Affiliation(s)
- Franziska Ziolkowski
- Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Oliver Busch
- Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Ingrid Mertig
- Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Jürgen Henk
- Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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28
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Kobayashi Y, Leone SR. Characterizing coherences in chemical dynamics with attosecond time-resolved x-ray absorption spectroscopy. J Chem Phys 2022; 157:180901. [DOI: 10.1063/5.0119942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Coherence can drive wave-like motion of electrons and nuclei in photoexcited systems, which can yield fast and efficient ways to exert materials’ functionalities beyond the thermodynamic limit. The search for coherent phenomena has been a central topic in chemical physics although their direct characterization is often elusive. Here, we highlight recent advances in time-resolved x-ray absorption spectroscopy (tr-XAS) to investigate coherent phenomena, especially those that utilize the eminent light source of isolated attosecond pulses. The unparalleled time and state sensitivities of tr-XAS in tandem with the unique element specificity render the method suitable to study valence electronic dynamics in a wide variety of materials. The latest studies have demonstrated the capabilities of tr-XAS to characterize coupled electronic–structural coherence in small molecules and coherent light–matter interactions of core-excited excitons in solids. We address current opportunities and challenges in the exploration of coherent phenomena, with potential applications for energy- and bio-related systems, potential crossings, strongly driven solids, and quantum materials. With the ongoing developments in both theory and light sources, tr-XAS holds great promise for revealing the role of coherences in chemical dynamics.
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Affiliation(s)
- Yuki Kobayashi
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
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29
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Sharma S, Shallcross S, Elliott P, Dewhurst JK. Making a case for femto-phono-magnetism with FePt. SCIENCE ADVANCES 2022; 8:eabq2021. [PMID: 36103545 PMCID: PMC9473611 DOI: 10.1126/sciadv.abq2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
In the field of femtomagnetism, magnetic matter is controlled by ultrafast laser pulses; here, we show that coupling phonon excitations of the nuclei to spin and charge leads to femto-phono-magnetism, a powerful route to control magnetic order at ultrafast times. With state-of-the-art theoretical simulations of coupled spin, charge, and lattice dynamics, we identify strong nonadiabatic spin-phonon coupled modes that dominate early time spin dynamics. Activating these phonon modes that we show leads to an additional (up to 40% extra) loss of moment in iron-platinum occurring within 40 femtoseconds of the pump laser pulse. Underpinning this enhanced ultrafast loss of spin moment, we identify a physical mechanism in which minority spin current drives an enhanced intersite minority charge transfer, in turn promoting increased on-site spin flips. Our finding demonstrates that the nuclear system, often assumed to play the role of an energy and angular momentum sink, when selectively preexcited, can play a profound role in controlling femtosecond spin dynamics in materials.
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Affiliation(s)
- Sangeeta Sharma
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Sam Shallcross
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Peter Elliott
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - J. Kay Dewhurst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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30
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Tsai MS, Liang AY, Tsai CL, Lai PW, Lin MW, Chen MC. Nonlinear compression toward high-energy single-cycle pulses by cascaded focus and compression. SCIENCE ADVANCES 2022; 8:eabo1945. [PMID: 35921417 PMCID: PMC9348793 DOI: 10.1126/sciadv.abo1945] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 06/21/2022] [Indexed: 05/31/2023]
Abstract
The advancement of contemporary ultrafast science requires reliable sources to provide high-energy few-cycle light pulses. Through experiments and simulations, we demonstrate an arrangement of pulse postcompression, referred to as cascaded focus and compression (CASCADE), for generating millijoule-level, single-cycle pulses in a compact fashion. CASCADE is realized by a series of foci in matter, whereas pulse compression is provided immediately after each focus to maintain a high efficiency of spectral broadening. By implementing four stages of CASCADE in argon cells, we achieve 50-fold compression of millijoule-level pulses at 1030 nanometers from 157 to 3.1 femtoseconds, with an output pulse energy of 0.98 millijoules and a transmission efficiency of 73%. When driving high harmonic generation, these single-cycle pulses enable the creation of a carrier-envelope phase-dependent extreme ultraviolet continuum with energies extending up to 180 electron volts, providing isolated attosecond pulses at the output.
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Affiliation(s)
- Ming-Shian Tsai
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - An-Yuan Liang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Chia-Lun Tsai
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Po-Wei Lai
- Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Ming-Wei Lin
- Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Ming-Chang Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu 300044, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, Taiwan
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31
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Li S, Zhou L, Frauenheim T, He J. Light-Controlled Ultrafast Magnetic State Transition in Antiferromagnetic-Ferromagnetic van der Waals Heterostructures. J Phys Chem Lett 2022; 13:6223-6229. [PMID: 35770897 DOI: 10.1021/acs.jpclett.2c01476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Manipulating spin in antiferromagnetic (AFM) materials has great potential in AFM opto-spintronics. Laser pulses can induce a transient ferromagnetic (FM) state in AFM metallic systems but have never been proven in two-dimensional (2D) AFM semiconductors and related van der Waals (vdW) heterostructures. Herein, using 2D vdW heterostructures of FM MnS2 and AFM MXenes as prototypes, we investigated optically induced interlayer spin transfer dynamics based on real-time time-dependent density functional theory. We observed that laser pulses induce significant spin injection and interfacial atom-mediated spin transfer from MnS2 to Cr2CCl2. In particular, we first demonstrated the transient FM state in semiconducting AFM-FM heterostructures during photoexcited processes. The proximity magnetism breaks the magnetic symmetry of Cr2CCl2 in heterostructures. Our results provide a microscopic understanding of optically controlled interlayer spin dynamics in 2D magnetic heterostructures and open a new way to manipulate magnetic order in 2D materials for ultrafast opto-spintronics.
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Affiliation(s)
- Shuo Li
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China
- Beijing Computational Science Research Center, Beijing 100193, P. R. China
| | - Liujiang Zhou
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Thomas Frauenheim
- Beijing Computational Science Research Center, Beijing 100193, P. R. China
- Bremen Center for Computational Materials Science, University of Bremen, Bremen 28359, Germany
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen 518110, P. R. China
| | - Junjie He
- Bremen Center for Computational Materials Science, University of Bremen, Bremen 28359, Germany
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Prague 12843, Czechia
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32
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Yao K, Steinbach F, Borchert M, Schick D, Engel D, Bencivenga F, Mincigrucci R, Foglia L, Pedersoli E, De Angelis D, Pancaldi M, Wehinger B, Capotondi F, Masciovecchio C, Eisebitt S, von Korff Schmising C. All-Optical Switching on the Nanometer Scale Excited and Probed with Femtosecond Extreme Ultraviolet Pulses. NANO LETTERS 2022; 22:4452-4458. [PMID: 35605204 DOI: 10.1021/acs.nanolett.2c01060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultrafast control of magnetization on the nanometer length scale, in particular all-optical switching, is key to putting ultrafast magnetism on the path toward future technological application in data storage technology. However, magnetization manipulation with light on this length scale is challenging due to the wavelength limitations of optical radiation. Here, we excite transient magnetic gratings in a GdFe alloy with a periodicity of 87 nm by the interference of two coherent femtosecond light pulses in the extreme ultraviolet spectral range. The subsequent ultrafast evolution of the magnetization pattern is probed by diffraction of a third, time-delayed pulse tuned to the Gd N-edge at a wavelength of 8.3 nm. By examining the simultaneously recorded first and second order diffractions and by performing reference real-space measurements with a wide-field magneto-optical microscope with femtosecond time resolution, we can conclusively demonstrate the ultrafast emergence of all-optical switching on the nanometer length scale.
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Affiliation(s)
- Kelvin Yao
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Felix Steinbach
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Martin Borchert
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Daniel Schick
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Dieter Engel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Filippo Bencivenga
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Riccardo Mincigrucci
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Laura Foglia
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Emanuele Pedersoli
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Dario De Angelis
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Matteo Pancaldi
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Björn Wehinger
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, via Torino 155, 30172 Venezia Mestre, Italy
| | - Flavio Capotondi
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Claudio Masciovecchio
- Elettra Sincrotrone Trieste S.C.p.A., Strada Statale 14 km 163.5, 34149 Basovizza, Trieste, Italy
| | - Stefan Eisebitt
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
- Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Clemens von Korff Schmising
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
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33
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Borrego-Varillas R, Lucchini M, Nisoli M. Attosecond spectroscopy for the investigation of ultrafast dynamics in atomic, molecular and solid-state physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:066401. [PMID: 35294930 DOI: 10.1088/1361-6633/ac5e7f] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Since the first demonstration of the generation of attosecond pulses (1 as = 10-18s) in the extreme-ultraviolet spectral region, several measurement techniques have been introduced, at the beginning for the temporal characterization of the pulses, and immediately after for the investigation of electronic and nuclear ultrafast dynamics in atoms, molecules and solids with unprecedented temporal resolution. The attosecond spectroscopic tools established in the last two decades, together with the development of sophisticated theoretical methods for the interpretation of the experimental outcomes, allowed to unravel and investigate physical processes never observed before, such as the delay in photoemission from atoms and solids, the motion of electrons in molecules after prompt ionization which precede any notable nuclear motion, the temporal evolution of the tunneling process in dielectrics, and many others. This review focused on applications of attosecond techniques to the investigation of ultrafast processes in atoms, molecules and solids. Thanks to the introduction and ongoing developments of new spectroscopic techniques, the attosecond science is rapidly moving towards the investigation, understanding and control of coupled electron-nuclear dynamics in increasingly complex systems, with ever more accurate and complete investigation techniques. Here we will review the most common techniques presenting the latest results in atoms, molecules and solids.
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Affiliation(s)
- Rocío Borrego-Varillas
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Matteo Lucchini
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Mauro Nisoli
- Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche (CNR), Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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Svoboda V, Waters MDJ, Zindel D, Wörner HJ. Generation and complete polarimetry of ultrashort circularly polarized extreme-ultraviolet pulses. OPTICS EXPRESS 2022; 30:14358-14367. [PMID: 35473180 DOI: 10.1364/oe.449411] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
The generation of ultrashort circularly polarized pulses in the extreme-ultraviolet spectral range has recently attracted considerable interest for applications in time-resolved circular-dichroism experiments. Here, we demonstrate a simple approach to generate near-circularly polarized femtosecond pulses in the vacuum-ultraviolet. The ellipticity of the generated light can be continuously tuned from linear to near-circular, as demonstrated by detailed polarimetry measurements. Combining optical polarimetry with photoelectron circular-dichroism (PECD) measurements, we demonstrate a novel approach to characterizing the polarization state of light in terms of all four Stokes parameters. For photon energies of 9.3 eV, we obtained S3 = 0.96 ± 0.02 and a degree of polarization of 97±2%, i.e. the highest values reported from any harmonic-generation source so far. This source is directly applicable to circular-dichroism experiments, also enabling time-resolved PECD in the extreme-ultraviolet, a general approach to probing time-dependent chirality during chemical processes on (sub)-femtosecond time scales.
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35
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Li P, Liu S, Chen X, Geng C, Wu X. Spintronic terahertz emission with manipulated polarization (STEMP). FRONTIERS OF OPTOELECTRONICS 2022; 15:12. [PMID: 36637604 PMCID: PMC9756272 DOI: 10.1007/s12200-022-00011-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/11/2022] [Indexed: 06/17/2023]
Abstract
Highly efficient generation and arbitrary manipulation of spin-polarized terahertz (THz) radiation will enable chiral lightwave driven quantum nonequilibrium state regulation, induce new electronic structures, consequently provide a powerful experimental tool for investigation of nonlinear THz optics and extreme THz science and applications. THz circular dichromic spectroscopy, ultrafast electron bunch manipulation, as well as THz imaging, sensing, and telecommunication, also need chiral THz waves. Here we review optical generation of circularly-polarized THz radiation but focus on recently emerged polarization tunable spintronic THz emission techniques, which possess many advantages of ultra-broadband, high efficiency, low cost, easy for integration and so on. We believe that chiral THz sources based on the combination of electron spin, ultrafast optical techniques and material structure engineering will accelerate the development of THz science and applications.
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Affiliation(s)
- Peiyan Li
- School of Electronic and Information Engineering, Beihang University, Beijing, 100191, China
| | - Shaojie Liu
- School of Cyber Science and Technology, Beihang University, Beijing, 100191, China
| | - Xinhou Chen
- School of Electronic and Information Engineering, Beihang University, Beijing, 100191, China
| | - Chunyan Geng
- School of Electronic and Information Engineering, Beihang University, Beijing, 100191, China
| | - Xiaojun Wu
- School of Electronic and Information Engineering, Beihang University, Beijing, 100191, China.
- School of Cyber Science and Technology, Beihang University, Beijing, 100191, China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Rupprecht P, Aufleger L, Heinze S, Magunia A, Ding T, Rebholz M, Amberg S, Mollov N, Henrich F, Haverkort MW, Ott C, Pfeifer T. Laser Control of Electronic Exchange Interaction within a Molecule. PHYSICAL REVIEW LETTERS 2022; 128:153001. [PMID: 35499899 DOI: 10.1103/physrevlett.128.153001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/01/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Electronic interactions play a fundamental role in atoms, molecular structure and reactivity. We introduce a general concept to control the effective electronic exchange interaction with intense laser fields via coupling to excited states. As an experimental proof of principle, we study the SF_{6} molecule using a combination of soft x-ray and infrared (IR) laser pulses. Increasing the IR intensity increases the effective exchange energy of the core hole with the excited electron by 50%, as observed by a characteristic spin-orbit branching ratio change. This work demonstrates altering electronic interactions by targeting many-particle quantum properties.
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Affiliation(s)
- Patrick Rupprecht
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Lennart Aufleger
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Simon Heinze
- Institut für theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany
| | - Alexander Magunia
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Thomas Ding
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Marc Rebholz
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Stefano Amberg
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Nikola Mollov
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Felix Henrich
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Maurits W Haverkort
- Institut für theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany
| | - Christian Ott
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Thomas Pfeifer
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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Formisano F, Dubrovin RM, Pisarev RV, Kalashnikova AM, Kimel AV. Laser-induced THz magnetism of antiferromagnetic CoF 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:225801. [PMID: 35263728 DOI: 10.1088/1361-648x/ac5c20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Excitation, detection, and control of coherent THz magnetic excitation in antiferromagnets are challenging problems that can be addressed using ever shorter laser pulses. We study experimentally excitation of magnetic dynamics at THz frequencies in an antiferromagnetic insulator CoF2by sub-10 fs laser pulses. Time-resolved pump-probe polarimetric measurements at different temperatures and probe polarizations reveal laser-induced transient circular birefringence oscillating at the frequency of 7.45 THz and present below the Néel temperature. The THz oscillations of circular birefringence are ascribed to oscillations of the magnetic moments of Co2+ions induced by the laser-driven coherentEgphonon mode via the THz analogue of the transverse piezomagnetic effect. It is also shown that the same pulse launches coherent oscillations of the magnetic linear birefringence at the frequency of 3.4 THz corresponding to the two-magnon mode. Analysis of the probe polarization dependence of the transient magnetic linear birefringence at the frequency of the two-magnon mode enables identifying its symmetry.
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Affiliation(s)
- F Formisano
- Institute for Molecules and Materials, Radboud University, 6571AJ Nijmegen, The Netherlands
| | | | - R V Pisarev
- Ioffe Institute, 194021 St. Petersburg, Russia
| | | | - A V Kimel
- Institute for Molecules and Materials, Radboud University, 6571AJ Nijmegen, The Netherlands
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38
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Ultrafast time-evolution of chiral Néel magnetic domain walls probed by circular dichroism in x-ray resonant magnetic scattering. Nat Commun 2022; 13:1412. [PMID: 35301298 PMCID: PMC8931105 DOI: 10.1038/s41467-022-28899-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 02/18/2022] [Indexed: 11/29/2022] Open
Abstract
Non-collinear spin textures in ferromagnetic ultrathin films are attracting a renewed interest fueled by possible fine engineering of several magnetic interactions, notably the interfacial Dzyaloshinskii-Moriya interaction. This allows for the stabilization of complex chiral spin textures such as chiral magnetic domain walls (DWs), spin spirals, and magnetic skyrmions among others. We report here on the behavior of chiral DWs at ultrashort timescale after optical pumping in perpendicularly magnetized asymmetric multilayers. The magnetization dynamics is probed using time-resolved circular dichroism in x-ray resonant magnetic scattering (CD-XRMS). We observe a picosecond transient reduction of the CD-XRMS, which is attributed to the spin current-induced coherent and incoherent torques within the continuously varying spin texture of the DWs. We argue that a specific demagnetization of the inner structure of the DW induces a flow of spins from the interior of the neighboring magnetic domains. We identify this time-varying change of the DW texture shortly after the laser pulse as a distortion of the homochiral Néel shape toward a transient mixed Bloch-Néel-Bloch texture along a direction transverse to the DW. There is interest in encoding of information in complex spin structures present in magnetic systems, such as domain walls. Here, Léveillé et al study the ultrafast dynamics of chiral domain walls, and show the emergence of a transient spin chiral texture at the domain wall.
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39
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Tauchert SR, Volkov M, Ehberger D, Kazenwadel D, Evers M, Lange H, Donges A, Book A, Kreuzpaintner W, Nowak U, Baum P. Polarized phonons carry angular momentum in ultrafast demagnetization. Nature 2022; 602:73-77. [PMID: 35110761 DOI: 10.1038/s41586-021-04306-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 12/01/2021] [Indexed: 11/10/2022]
Abstract
Magnetic phenomena are ubiquitous in nature and indispensable for modern science and technology, but it is notoriously difficult to change the magnetic order of a material in a rapid way. However, if a thin nickel film is subjected to ultrashort laser pulses, it loses its magnetic order almost completely within femtosecond timescales1. This phenomenon is widespread2-7 and offers opportunities for rapid information processing8-11 or ultrafast spintronics at frequencies approaching those of light8,9,12. Consequently, the physics of ultrafast demagnetization is central to modern materials research1-7,13-28, but a crucial question has remained elusive: if a material loses its magnetization within mere femtoseconds, where is the missing angular momentum in such a short time? Here we use ultrafast electron diffraction to reveal in nickel an almost instantaneous, long-lasting, non-equilibrium population of anisotropic high-frequency phonons that appear within 150-750 fs. The anisotropy plane is perpendicular to the direction of the initial magnetization and the atomic oscillation amplitude is 2 pm. We explain these observations by means of circularly polarized phonons that quickly absorb the angular momentum of the spin system before macroscopic sample rotation. The time that is needed for demagnetization is related to the time it takes to accelerate the atoms. These results provide an atomistic picture of the Einstein-de Haas effect and signify the general importance of polarized phonons for non-equilibrium dynamics and phase transitions.
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Affiliation(s)
- S R Tauchert
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany.,Ludwig-Maximilians-Universität München, Garching, Germany
| | - M Volkov
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany.,Ludwig-Maximilians-Universität München, Garching, Germany
| | - D Ehberger
- Ludwig-Maximilians-Universität München, Garching, Germany
| | - D Kazenwadel
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - M Evers
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - H Lange
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - A Donges
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - A Book
- Technische Universität München, Physik-Department E21, Garching, Germany
| | - W Kreuzpaintner
- Technische Universität München, Physik-Department E21, Garching, Germany.,Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing, China.,Spallation Neutron Source Science Center, Dongguan, China
| | - U Nowak
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany
| | - P Baum
- Universität Konstanz, Fachbereich Physik, Konstanz, Germany. .,Ludwig-Maximilians-Universität München, Garching, Germany.
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40
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Liu N, Zhou S, Zhao J. Photoinduced Spin Injection and Ferromagnetism in 2D Group III Monochalcogenides. J Phys Chem Lett 2022; 13:590-597. [PMID: 35015540 DOI: 10.1021/acs.jpclett.1c03994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Strong light-matter interactions in low-dimensional materials offer an opportunity for flexible property-tuning by optical switching. Herein, we exploit photoexcitation for spin injection into semiconductors by rationally designing heterojunctions having distinct dynamic behavior for photocarriers in two spin channels. As a proof-of-concept, we trigger homogeneous magnetism in a group III monochalcogenide monolayer (MX with M = In, Ga; X = S, Se) by placing it on a ferromagnetic CrI3 substrate under light illumination. Our time-dependent ab initio nonadiabatic molecular dynamics simulations reveal fast electron-hole separation for the majority spin channel but rapid recombination for the minority spin channel at this heterostructure. The majority carriers cause hole doping and strong ferromagnetic ordering in the MX sheet, with magnetic moment tunable by the injected carriers' concentration. The interplay between photoexcited hole carriers, the Van Hove singularity of MX monolayers, and interfacial charge transfer provides essential physical insights for nondestructively manipulating charge and spin in two-dimensional semiconductors via light switching.
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Affiliation(s)
- Nanshu Liu
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, P.R. China
| | - Si Zhou
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
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41
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Zhu B, Fu Z, Chen Y, Peng S, Jin C, Fan G, Zhang S, Wang S, Ru H, Tian C, Wang Y, Kapteyn H, Murnane M, Tao Z. Spatially homogeneous few-cycle compression of Yb lasers via all-solid-state free-space soliton management. OPTICS EXPRESS 2022; 30:2918-2932. [PMID: 35209423 DOI: 10.1364/oe.443942] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The high power and variable repetition-rate of Yb femtosecond lasers makes them very attractive for ultrafast science. However, for capturing sub-200 fs dynamics, efficient, high-fidelity and high-stability pulse compression techniques are essential. Spectral broadening using an all-solid-state free-space geometry is particularly attractive, as it is simple, robust and low-cost. However, spatial and temporal losses caused by spatio-spectral inhomogeneities have been a major challenge to date, due to coupled space-time dynamics associated with unguided nonlinear propagation. In this work, we use all-solid-state free-space compressors to demonstrate compression of 170 fs pulses at a wavelength of 1030nm from a Yb:KGW laser to ∼9.2 fs, with a highly spatially homogeneous mode. This is achieved by ensuring that the nonlinear beam propagation in periodic layered Kerr media occurs in spatial soliton modes, and by confining the nonlinear phase through each material layer to less than 1.0 rad. A remarkable spatio-spectral homogeneity of ∼0.87 can be realized, which yields a high efficiency of >50% for few-cycle compression. The universality of the method is demonstrated by implementing high-quality pulse compression under a wide range of laser conditions. The high spatiotemporal quality and the exceptional stability of the compressed pulses are further verified by high-harmonic generation. Our predictive method offers a compact and cost-effective solution for high-quality few-cycle-pulse generation from Yb femtosecond lasers, and will enable broad applications in ultrafast science and extreme nonlinear optics.
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42
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Wu C, Li L, Yeung M, Wu S, Cousens S, Tietze S, Dromey B, Zhou C, Ruan S, Zepf M. Proposal for complete characterization of attosecond pulses from relativistic plasmas. OPTICS EXPRESS 2022; 30:389-402. [PMID: 35201216 DOI: 10.1364/oe.444043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
In this study, we propose two full-optical-setup and single-shot measurable approaches for complete characterization of attosecond pulses from surface high harmonic generation (SHHG): SHHG-SPIDER (spectral phase interferometry for direct electric field reconstruction) and SHHG-SEA-SPIDER (spatially encoded arrangement for SPIDER). 1D- and 2D-EPOCH PIC (particle-in-cell) simulations were performed to generate the attosecond pulses from relativistic plasmas under different conditions. Pulse trains dominated by single isolated peak as well as complex pulse train structures are extensively discussed for both methods, which showed excellent accuracy in the complete reconstruction of the attosecond field with respect to the direct Fourier transformed result. Kirchhoff integral theorem has been used for the near-to-far-field transformation. This far-field propagation method allows us to relate these results to potential experimental implementations of the scheme. The impact of comprehensive experimental parameters for both apparatus, such as spectral shear, spatial shear, cross-angle, time delay, and intensity ratio between the two replicas has been investigated thoroughly. These methods are applicable to complete characterization for SHHG attosecond pulses driven by a few to hundreds of terawatts femtosecond laser systems.
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43
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Sato SA. Two-step Brillouin zone sampling for efficient computation of electron dynamics in solids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:095903. [PMID: 34852332 DOI: 10.1088/1361-648x/ac3f00] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
We develop a numerical Brillouin-zone integration scheme for real-time propagation of electronic systems with time-dependent density functional theory. This scheme is based on the decomposition of a large simulation into a set of small independent simulations. The performance of the decomposition scheme is examined in both linear and nonlinear regimes by computing the linear optical properties of bulk silicon and high-order harmonic generation. The decomposition of a large simulation into a set of independent simulations can improve the efficiency of parallel computation by reducing communication and synchronization overhead and enhancing the portability of simulations across a relatively small cluster machine.
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Affiliation(s)
- Shunsuke A Sato
- Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
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44
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Li D, Li S, Zhong C, He J. Tuning magnetism at the two-dimensional limit: a theoretical perspective. NANOSCALE 2021; 13:19812-19827. [PMID: 34825688 DOI: 10.1039/d1nr06835k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The discovery of two-dimensional (2D) magnetic materials provides an ideal testbed for manipulating the magnetic properties at the atomically thin and 2D limit. This review gives recent progress in the emergent 2D magnets and heterostructures, focusing on the theory side. We summarize different theoretical models, ranging from the atomic to micrometer-scale, used to describe magnetic orders. Then, the current strategies for tuning magnetism in 2D materials are further discussed, such as electric field, magnetic field, strain, optics, chemical functionalization, and spin-orbit engineering. Finally, we conclude with the future challenges and opportunities for 2D magnetism.
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Affiliation(s)
- Dongzhe Li
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Shuo Li
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Chengyong Zhong
- Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
| | - Junjie He
- Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 2835, Bremen, Germany
- Department of Physical and Macromolecular Chemistry & Charles University Centre of Advanced Materials, Faculty of Science, Charles University in Prague, Hlavova 8, Prague 2, 128 43, Czech Republic.
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45
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Zayko S, Kfir O, Heigl M, Lohmann M, Sivis M, Albrecht M, Ropers C. Ultrafast high-harmonic nanoscopy of magnetization dynamics. Nat Commun 2021; 12:6337. [PMID: 34732725 PMCID: PMC8566501 DOI: 10.1038/s41467-021-26594-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 08/10/2021] [Indexed: 11/25/2022] Open
Abstract
Light-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and nanometers, respectively. Pump-probe spectroscopy and diffraction studies indicate that spatio-temporal dynamics may drastically affect the non-equilibrium magnetic evolution. Yet, direct real-space magnetic imaging on the relevant timescales has remained challenging. Here, we demonstrate ultrafast high-harmonic nanoscopy employing circularly polarized high-harmonic radiation for real-space imaging of femtosecond magnetization dynamics. We map quenched magnetic domains and localized spin structures in Co/Pd multilayers with a sub-wavelength spatial resolution down to 16 nm, and strobosocopically trace the local magnetization dynamics with 40 fs temporal resolution. Our compact experimental setup demonstrates the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with high sensitivity to chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics.
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Affiliation(s)
- Sergey Zayko
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany.
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
| | - Ofer Kfir
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
- School of Electrical Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Michael Heigl
- Institute of Physics, University of Augsburg, 86159, Augsburg, Germany
| | - Michael Lohmann
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
| | - Murat Sivis
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Manfred Albrecht
- Institute of Physics, University of Augsburg, 86159, Augsburg, Germany
| | - Claus Ropers
- 4th Physical Institute-Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
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46
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Leblanc A, Longa A, Kumar M, Laramée A, Dansereau C, Ibrahim H, Lassonde P, Légaré F. Temporal characterization of two-octave infrared pulses by frequency resolved optical switching. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/ac184f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
We present the temporal characterization of infrared pulses with spectra extending from 0.55 to 2.5 μm by using the frequency resolved optical switching (FROSt) technique. The pulses are obtained by broadening femtosecond pulses at 1.75 μm central wavelength in a two-stage hollow core fiber setup. This work demonstrates the capability of the FROSt technique to temporally characterize pulses with ultra-broadband spectra. Being free of phase-matching constraints, it enables the characterization of pulses with very low energy at the limit of the detection threshold and with arbitrary long pulse duration. This strength of the FROSt technique is illustrated by the characterization of supercontinua pulses whose spectra span over two octaves and with only 150 nJ energy that is spread temporally over almost 40 ps. The FROSt capabilities provide a versatile tool for the characterization of sub-cycle pulses and to study nonlinear processes such as supercontinuum generation.
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47
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Liu X, Merhe A, Jal E, Delaunay R, Jarrier R, Chardonnet V, Hennes M, Chiuzbaian SG, Légaré K, Hennecke M, Radu I, Von Korff Schmising C, Grunewald S, Kuhlmann M, Lüning J, Vodungbo B. Sub-15-fs X-ray pump and X-ray probe experiment for the study of ultrafast magnetization dynamics in ferromagnetic alloys. OPTICS EXPRESS 2021; 29:32388-32403. [PMID: 34615311 DOI: 10.1364/oe.430828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
In this paper, we present a new setup for the measurement of element-specific ultrafast magnetization dynamics in ferromagnetic thin films with a sub-15-fs time resolution. Our experiment relies on a split and delay approach which allows us to fully exploit the shortest X-rays pulses delivered by X-ray Free Electrons Lasers (close to the attosecond range), in an X-ray pump - X-ray probe geometry. The setup performance is demonstrated by measuring the ultrafast elemental response of Ni and Fe during demagnetization of ferromagnetic Ni and Ni80Fe20 (Permalloy) samples upon resonant excitation at the corresponding absorption edges. The transient demagnetization process is measured in both reflection and transmission geometry using, respectively, the transverse magneto-optical Kerr effect (T-MOKE) and the Faraday effect as probing mechanisms.
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Luo X, Obeysekera D, Won C, Sung SH, Schnitzer N, Hovden R, Cheong SW, Yang J, Sun K, Zhao L. Ultrafast Modulations and Detection of a Ferro-Rotational Charge Density Wave Using Time-Resolved Electric Quadrupole Second Harmonic Generation. PHYSICAL REVIEW LETTERS 2021; 127:126401. [PMID: 34597104 DOI: 10.1103/physrevlett.127.126401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/04/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
We show the ferro-rotational nature of the commensurate charge density wave (CCDW) in 1T-TaS_{2} and track its dynamic modulations by temperature-dependent and time-resolved electric quadrupole rotation anisotropy-second harmonic generation (EQ RA-SHG), respectively. The ultrafast modulations manifest as the breathing and the rotation of the EQ RA-SHG patterns at three frequencies around the reported single CCDW amplitude mode frequency. A sudden shift of the triplet frequencies and a dramatic increase in the breathing and rotation magnitude further reveal a photoinduced transient CDW phase across a critical pump fluence of ∼0.5 mJ/cm^{2}.
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Affiliation(s)
- Xiangpeng Luo
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
| | - Dimuthu Obeysekera
- Department of Physics, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, New Jersey 07102, USA
| | - Choongjae Won
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Suk Hyun Sung
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Noah Schnitzer
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Robert Hovden
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, New Jersey 07102, USA
| | - Kai Sun
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
| | - Liuyan Zhao
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
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Zhao HC, Xia H, Hu S, Lv YY, Zhao ZR, He J, Liang E, Ni G, Chen LY, Qiu XP, Zhou SM, Zhao HB. Large ultrafast-modulated Voigt effect in noncollinear antiferromagnet Mn 3Sn. Nat Commun 2021; 12:5266. [PMID: 34489461 PMCID: PMC8421456 DOI: 10.1038/s41467-021-25654-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 08/18/2021] [Indexed: 11/15/2022] Open
Abstract
The time-resolved magneto-optical (MO) Voigt effect can be utilized to study the Néel order dynamics in antiferromagnetic (AFM) materials, but it has been limited for collinear AFM spin configuration. Here, we have demonstrated that in Mn3Sn with an inverse triangular spin structure, the quench of AFM order by ultrafast laser pulses can result in a large Voigt effect modulation. The modulated Voigt angle is significantly larger than the polarization rotation due to the crystal-structure related linear dichroism effect and the modulated MO Kerr angle arising from the ferroic ordering of cluster magnetic octupole. The AFM order quench time shows negligible change with increasing temperature approaching the Néel temperature (TN), in markedly contrast with the pronounced slowing-down demagnetization typically observed in conventional magnetic materials. This atypical behavior can be explained by the influence of weakened Dzyaloshinskii–Moriya interaction rather than the smaller exchange splitting on the diminished AFM order near TN. The temperature-insensitive ultrafast spin manipulation can pave the way for high-speed spintronic devices either working at a wide range of temperature or demanding spin switching near TN. Mn3Sn is an anti-ferromagnetic material which displays a large magneto-optical Kerr effect, despite lacking a ferromagnetic moment. Here, the authors show that likewise, Mn3Sn, also presents a particularly large magneto-optical Voigt signal, with a negligible change in the quench time over a wide temperature range.
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Affiliation(s)
- H C Zhao
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China
| | - H Xia
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China.,Department of Physics, Fudan University, Shanghai, China
| | - S Hu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China
| | - Y Y Lv
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China
| | - Z R Zhao
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China
| | - J He
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China
| | - E Liang
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China
| | - G Ni
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China.
| | - L Y Chen
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China
| | - X P Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China.
| | - S M Zhou
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China.
| | - H B Zhao
- Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China. .,Shanghai Frontier Base of Intelligent Optoelectronics and Perception, Institute of Optoelectronics, Fudan University, Shanghai, China.
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50
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Panda SN, Majumder S, Choudhury S, Bhattacharya A, Sinha S, Barman A. Femtosecond laser-induced spin dynamics in single-layer graphene/CoFeB thin films. NANOSCALE 2021; 13:13709-13718. [PMID: 34477646 DOI: 10.1039/d1nr03397b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Graphene/ferromagnet hybrid heterostructures are important building blocks of spintronics due to the unique ability of graphene to transport spin current over unprecedented distances and possible increase in its spin-orbit coupling due to proximity and hybridization. Here, we present magnetization dynamics over a femtosecond to nanosecond timescale by employing an all-optical time-resolved magneto-optical Kerr effect technique in single-layer graphene (SLG)/CoFeB thin films with varying CoFeB thickness and compared them with reference CoFeB thin films without an SLG underlayer. Gilbert damping variation with CoFeB thickness is modelled to extract spin-mixing conductance for the SLG/CoFeB interface and isolate the two-magnon scattering contribution from spin pumping. In SLG/CoFeB, we have established an inverse relationship between ultrafast demagnetization time (τm) and the Gilbert damping parameter (α) induced by interfacial spin accumulation and pure spin-current transport via a spin pumping mechanism. This systematic study of ultrafast demagnetization in SLG/CoFeB heterostructures and its connection with magnetic damping can help to design graphene-based ultrahigh-speed spintronic devices.
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Affiliation(s)
- Surya Narayan Panda
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India.
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