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Kimura SI, Kawabata T, Matsumoto H, Ohta Y, Yoshizumi A, Yoshida Y, Yamashita T, Watanabe H, Ohtsubo Y, Yamamoto N, Jin X. Bulk-sensitive spin-resolved resonant electron energy-loss spectroscopy (SR-rEELS): Observation of element- and spin-selective bulk plasmons. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:093103. [PMID: 34598542 DOI: 10.1063/5.0055435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
We have developed spin-resolved resonant electron energy-loss spectroscopy with the primary energy of 0.3-1.5 keV, which corresponds to the core excitations of 2p-3d absorption of transition metals and 3d-4f absorption of rare-earths, with the energy resolution of about 100 meV using a spin-polarized electron source as a GaAs/GaAsP strained superlattice photocathode. Element- and spin-selective carrier and valence plasmons can be observed using the resonance enhancement of core absorptions and electron spin polarization. Furthermore, bulk-sensitive electron energy-loss spectroscopy spectra can be obtained because the primary energy corresponds to the mean free path of 1-10 nm. The methodology is expected to provide us with novel information about elementary excitations by resonant inelastic x-ray scattering and resonant photoelectron spectroscopy.
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Affiliation(s)
- Shin-Ichi Kimura
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Taishi Kawabata
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hiroki Matsumoto
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yu Ohta
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Ayuki Yoshizumi
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yuto Yoshida
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takumi Yamashita
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Hiroshi Watanabe
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yoshiyuki Ohtsubo
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Naoto Yamamoto
- High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
| | - Xiuguang Jin
- High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
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Gillmeister K, Golež D, Chiang CT, Bittner N, Pavlyukh Y, Berakdar J, Werner P, Widdra W. Ultrafast coupled charge and spin dynamics in strongly correlated NiO. Nat Commun 2020; 11:4095. [PMID: 32796844 PMCID: PMC7429846 DOI: 10.1038/s41467-020-17925-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 07/17/2020] [Indexed: 11/30/2022] Open
Abstract
Charge excitations across an electronic band gap play an important role in opto-electronics and light harvesting. In contrast to conventional semiconductors, studies of above-band-gap photoexcitations in strongly correlated materials are still in their infancy. Here we reveal the ultrafast dynamics controlled by Hund’s physics in strongly correlated photoexcited NiO. By combining time-resolved two-photon photoemission experiments with state-of-the-art numerical calculations, an ultrafast (≲10 fs) relaxation due to Hund excitations and related photo-induced in-gap states are identified. Remarkably, the weight of these in-gap states displays long-lived coherent THz oscillations up to 2 ps at low temperature. The frequency of these oscillations corresponds to the strength of the antiferromagnetic superexchange interaction in NiO and their lifetime vanishes slightly above the Néel temperature. Numerical simulations of a two-band t-J model reveal that the THz oscillations originate from the interplay between local many-body excitations and antiferromagnetic spin correlations. Nickel Oxide (NiO) is a strongly correlated insulator with antiferromagnetic (AFM) ordering. Here, using pump-probe photoemission on NiO, the authors observe coherent terahertz oscillations in the photoemission signal, a signature of an in-gap state coupled to the AFM background.
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Affiliation(s)
- Konrad Gillmeister
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
| | - Denis Golež
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010, USA.,Department of Physics, University of Fribourg, 1700, Fribourg, Switzerland
| | - Cheng-Tien Chiang
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
| | - Nikolaj Bittner
- Department of Physics, University of Fribourg, 1700, Fribourg, Switzerland
| | - Yaroslav Pavlyukh
- Department of Physics, Technische Universität Kaiserslautern, 67653, Kaiserslautern, Germany
| | - Jamal Berakdar
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700, Fribourg, Switzerland.
| | - Wolf Widdra
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany. .,Max Planck Institute of Microstructure Physics, 06120, Halle, Germany.
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Vasilyev D, Kirschner J. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:083902. [PMID: 27587131 DOI: 10.1063/1.4961471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We describe a new "complete" spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the "spin-polarizing mirror" type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å(-1), at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.
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Affiliation(s)
- D Vasilyev
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
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3s- and 3p-core level excitations in 3d-transition metal oxides from electron-energy-loss spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s002570050066] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Reinert F, Steiner P, Engel T, Hüfner S. Low energy excitations in KMnO4 with 1 eV<=ΔE<=10 eV from electron-energy loss spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s002570050031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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The Performance of Hybrid Density Functionals in Solid State Chemistry. STRUCTURE AND BONDING 2012. [DOI: 10.1007/b97944] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Fromme B, Möller M, Anschütz T, Bethke C, Kisker E. Electron-Exchange Processes in the Excitations of NiO(100) Surface d States. PHYSICAL REVIEW LETTERS 1996; 77:1548-1551. [PMID: 10063106 DOI: 10.1103/physrevlett.77.1548] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Fromme B, Koch C, Deussen R, Kisker E. Resonant exchange scattering in dipole-forbidden d-d excitations in NiO(100). PHYSICAL REVIEW LETTERS 1995; 75:693-697. [PMID: 10060090 DOI: 10.1103/physrevlett.75.693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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