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Plötzing M, Adam R, Weier C, Plucinski L, Eich S, Emmerich S, Rollinger M, Aeschlimann M, Mathias S, Schneider CM. Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:043903. [PMID: 27131684 DOI: 10.1063/1.4946782] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The fundamental mechanism responsible for optically induced magnetization dynamics in ferromagnetic thin films has been under intense debate since almost two decades. Currently, numerous competing theoretical models are in strong need for a decisive experimental confirmation such as monitoring the triggered changes in the spin-dependent band structure on ultrashort time scales. Our approach explores the possibility of observing femtosecond band structure dynamics by giving access to extended parts of the Brillouin zone in a simultaneously time-, energy- and spin-resolved photoemission experiment. For this purpose, our setup uses a state-of-the-art, highly efficient spin detector and ultrashort, extreme ultraviolet light pulses created by laser-based high-order harmonic generation. In this paper, we present the setup and first spin-resolved spectra obtained with our experiment within an acquisition time short enough to allow pump-probe studies. Further, we characterize the influence of the excitation with femtosecond extreme ultraviolet pulses by comparing the results with data acquired using a continuous wave light source with similar photon energy. In addition, changes in the spectra induced by vacuum space-charge effects due to both the extreme ultraviolet probe- and near-infrared pump-pulses are studied by analyzing the resulting spectral distortions. The combination of energy resolution and electron count rate achieved in our setup confirms its suitability for spin-resolved studies of the band structure on ultrashort time scales.
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Affiliation(s)
- M Plötzing
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - R Adam
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - C Weier
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - L Plucinski
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - S Eich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - S Emmerich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - M Rollinger
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - S Mathias
- Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen, Germany
| | - C M Schneider
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
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2
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Miyawaki J, Chainani A, Takata Y, Mulazzi M, Oura M, Senba Y, Ohashi H, Shin S. Out-of-plane nesting driven spin spiral in ultrathin Fe/Cu(001) films. PHYSICAL REVIEW LETTERS 2010; 104:066407. [PMID: 20366842 DOI: 10.1103/physrevlett.104.066407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Indexed: 05/29/2023]
Abstract
Epitaxial ultrathin Fe films on fcc Cu(001) exhibit a spin spiral (SS), in contrast to the ferromagnetism of bulk bcc Fe. We study the in-plane (IP) and out-of-plane (OP) Fermi surfaces (FSs) of the SS in 8 monolayer Fe/Cu(001) films using energy-dependent soft-x-ray momentum-resolved photoemission spectroscopy. We show that the SS originates in nested regions confined to OP FSs, which are drastically modified compared to IP FSs. From precise reciprocal-space maps in successive zones, we obtain the associated real space compressive strain of 1.5+/-0.5% along c axis. An autocorrelation analysis quantifies the incommensurate ordering vector q=(2pi/a)(0,0, approximately 0.86), favoring a SS and consistent with magneto-optic Kerr effect experiments. The results reveal the importance of IP and OP FS mapping for ultrathin films.
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Affiliation(s)
- J Miyawaki
- Excitation Order Research Team, RIKEN SPring-8 Center, Sayo-cho, Hyogo, 679-5148, Japan
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Xie YP, Wu YZ, Gong XG. Quantum-well states in a double-well system: an example of Cu/Co(Ni)/Cu. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:052203. [PMID: 21386334 DOI: 10.1088/0953-8984/22/5/052203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The quantum-well (QW) states in the Cu/Co double-well system are studied by first-principles calculations. We have shown that the monolayer Ni or Co as a heterogeneous spacer in Cu QW can not only disturb the QW states extending into the whole structure, but also create new QW states because of the interfaces introduced, resulting in sub-well-confining electrons. If the QW state energy in two sub-wells is close to each other, these two sub-well QW states can couple together. We have also demonstrated that monolayer Co and Ni spacers play different roles for modulating QW states at different energy levels, which also result in a complicated distribution of QW states. The obtained results are in good agreement with experiment data.
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Affiliation(s)
- Yao-Ping Xie
- Surface Physics Laboratory and Laboratory for Computational Physical Sciences, Fudan University, Shanghai 200433, People's Republic of China
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4
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Schmidt AB, Pickel M, Wiemhöfer M, Donath M, Weinelt M. Spin-dependent electron dynamics in front of a ferromagnetic surface. PHYSICAL REVIEW LETTERS 2005; 95:107402. [PMID: 16196964 DOI: 10.1103/physrevlett.95.107402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Indexed: 05/04/2023]
Abstract
Exchange splitting and dynamics of image-potential states in front of a 3 monolayer iron film on Cu(100) have been studied with time-, energy-, and spin-resolved bichromatic two-photon photoemission. For the first image-potential state n=1 we observe an exchange splitting of 56 +/- 10 meV and spin-dependent lifetimes of 16 +/- 2 fs for majority-spin and of 11 +/- 2 fs for minority-spin electrons, respectively. The time-resolved studies of both the population and the linewidth of image-potential states manifest that at the magnetic surface not only inelastic but also quasielastic scattering processes are spin dependent.
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5
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Wu YZ, Schmid AK, Altman MS, Jin XF, Qiu ZQ. Spin-dependent Fabry-Pérot interference from a Cu thin film grown on fcc Co(001). PHYSICAL REVIEW LETTERS 2005; 94:027201. [PMID: 15698221 DOI: 10.1103/physrevlett.94.027201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Indexed: 05/24/2023]
Abstract
Spin-dependent electron reflection from a Cu thin film grown on Co/Cu(001) was investigated using spin-polarized low-energy electron microscopy (SPLEEM). Fabry-Pe rot type interference was observed and is explained using the phase accumulation model. SPLEEM images of the Cu overlayer reveal magnetic domains in the Co underlayer, with the domain contrast oscillating with electron energy and Cu film thickness. This behavior is attributed to the spin-dependent electron reflectivity at the Cu/Co interface which leads to spin-dependent Fabry-Pe rot electron interference in the Cu film.
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Affiliation(s)
- Y Z Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
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6
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Gao X, Koveshnikov AN, Madjoe RH, Stockbauer RL, Kurtz RL. Dominance of the final state in photoemission mapping of the fermi surface of Co/Cu(001). PHYSICAL REVIEW LETTERS 2003; 90:037603. [PMID: 12570524 DOI: 10.1103/physrevlett.90.037603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2002] [Indexed: 05/24/2023]
Abstract
The Fermi surface of tetragonally distorted fcc Co films grown on Cu(001) has been investigated with first-principles calculations and compared with an experimental determination using angle-resolved photoemission. The angular distributions for hnu=21-45 eV are dominated by the structure of the final states rather than by the shape of the Fermi surface. Theoretical estimates of the photoemission matrix elements support this observation. This suggests that photoemission can have limitations in mapping Fermi surfaces, especially for materials that exhibit flat, closely spaced valence bands.
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Affiliation(s)
- Xingyu Gao
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA
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Altmann KN, Gilman N, Hayoz J, Willis RF, Himpsel FJ. Effect of magnetic doping on the electronic states of Ni. PHYSICAL REVIEW LETTERS 2001; 87:137201. [PMID: 11580621 DOI: 10.1103/physrevlett.87.137201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2000] [Indexed: 05/23/2023]
Abstract
Angle-resolved photoemission is used to determine the change in the electronic states of Ni induced by doping with Fe and Cr. Well-defined spin and k states are selected using high energy and k resolution combined with single crystal alloys. Iron suppresses the mean free path of minority spins only, while chromium suppresses both spins and decreases the magnetic splitting. The strong variation of these effects from one impurity to the other supports the concept of magnetic doping.
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Affiliation(s)
- K N Altmann
- Department of Physics, University of Wisconsin Madison, 1150 University Avenue, Madison, Wisconsin 53706-1390, USA
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Kawakami RK, Rotenberg E, Choi HJ, Escorcia-Aparicio EJ, Bowen MO, Wolfe JH, Arenholz E, Zhang ZD, Smith NV, Qiu ZQ. Quantum-well states in copper thin films. Nature 1999. [DOI: 10.1038/18178] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Valla T, Pervan P, Milun M, Hayden AB, Woodruff DP. Electronic structure of silver and copper ultrathin films on V(100): Quantum-well states. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:11786-11795. [PMID: 9984970 DOI: 10.1103/physrevb.54.11786] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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10
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Újfalussy B, Szunyogh L, Weinberger P. Magnetic anisotropy in Fe/Cu(001) overlayers and interlayers: The high-moment ferromagnetic phase. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:9883-9890. [PMID: 9984723 DOI: 10.1103/physrevb.54.9883] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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11
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Wallauer W, Fauster T. Exchange splitting of image states on Fe/Cu(100) and Co/Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:5086-5091. [PMID: 9986473 DOI: 10.1103/physrevb.54.5086] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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12
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Fanelsa A, Kisker E, Henk J, Feder R. Magnetic dichroism in valence-band photoemission from Co/Cu(001): Experiment and theory. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:2922-2930. [PMID: 9986150 DOI: 10.1103/physrevb.54.2922] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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13
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Hwang C, Himpsel FJ. Electronic states induced by interface doping of Cu/Ni(100) with Co. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:15368-15371. [PMID: 9980894 DOI: 10.1103/physrevb.52.15368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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14
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Pérez-Díaz JL, Muñoz MC. Fermi surface of ferromagnetic fcc cobalt. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:2471-2475. [PMID: 9981311 DOI: 10.1103/physrevb.52.2471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Li D, Pearson J, Mattson JE, Bader SD, Johnson PD. Photoemission study of quantum confinement by a finite barrier: Cu/Co(wedge)/Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:7195-7199. [PMID: 9977282 DOI: 10.1103/physrevb.51.7195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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16
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Anno E. Optical absorption of fcc Co particles: Properties of conduction electrons of fcc Co. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:17502-17506. [PMID: 9976156 DOI: 10.1103/physrevb.50.17502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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17
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Pérez-Díaz JL, Muñoz MC. Spin-polarized electrons at interfaces: Co/Cu systems. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:8824-8831. [PMID: 9974903 DOI: 10.1103/physrevb.50.8824] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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18
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Wu SC, Garrison K, Begley AM, Jona F, Johnson PD. Electronic structure and magnetism of the Rh{001} surface. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:14081-14084. [PMID: 10010374 DOI: 10.1103/physrevb.49.14081] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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19
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Haugan ME, Chen Q, Onellion M, Himpsel FJ. Unoccupied states of Cr on Au(100), Ag(100), and Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:14028-14031. [PMID: 10010360 DOI: 10.1103/physrevb.49.14028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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