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Monteseguro V, Ruiz-Fuertes J, Barreda-Argüeso JA, Meyerheim HL, Rosa AD, Rodríguez F. Comment on "Mechanisms for Pressure-Induced Isostructural Phase Transitions in EuO". Phys Rev Lett 2022; 128:099701. [PMID: 35302817 DOI: 10.1103/physrevlett.128.099701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Affiliation(s)
- V Monteseguro
- DCITIMAC, MALTA Consolider Team, Facultad de Ciencias, University of Cantabria, 39005 Santander, Spain
| | - J Ruiz-Fuertes
- DCITIMAC, MALTA Consolider Team, Facultad de Ciencias, University of Cantabria, 39005 Santander, Spain
| | - J A Barreda-Argüeso
- DCITIMAC, MALTA Consolider Team, Facultad de Ciencias, University of Cantabria, 39005 Santander, Spain
| | - H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - A D Rosa
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - F Rodríguez
- DCITIMAC, MALTA Consolider Team, Facultad de Ciencias, University of Cantabria, 39005 Santander, Spain
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2
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Förster S, Trautmann M, Roy S, Adeagbo WA, Zollner EM, Hammer R, Schumann FO, Meinel K, Nayak SK, Mohseni K, Hergert W, Meyerheim HL, Widdra W. Observation and Structure Determination of an Oxide Quasicrystal Approximant. Phys Rev Lett 2016; 117:095501. [PMID: 27610863 DOI: 10.1103/physrevlett.117.095501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Indexed: 06/06/2023]
Abstract
We report on the first observation of an approximant structure to the recently discovered two-dimensional oxide quasicrystal. Using scanning tunneling microscopy, low-energy electron diffraction, and surface x-ray diffraction in combination with ab initio calculations, the atomic structure and the bonding scheme are determined. The oxide approximant follows a 3^{2}.4.3.4 Archimedean tiling. Ti atoms reside at the corners of each tiling element and are threefold coordinated to oxygen atoms. Ba atoms separate the TiO_{3} clusters, leading to a fundamental edge length of the tiling 6.7 Å.
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Affiliation(s)
- S Förster
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - M Trautmann
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - S Roy
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - W A Adeagbo
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - E M Zollner
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - R Hammer
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - F O Schumann
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - K Meinel
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - S K Nayak
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - W Hergert
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - W Widdra
- Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Meyerheim HL, Robinson IK, Jahns V, Eng PJ, Moritz W. Coverage dependent adsorption sites in the K/Cu(100) system: A crystal truncation rod analysis. Z KRIST-CRYST MATER 2015. [DOI: 10.1524/zkri.1993.208.12.73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Roy S, Meyerheim HL, Ernst A, Mohseni K, Tusche C, Vergniory MG, Menshchikova TV, Otrokov MM, Ryabishchenkova AG, Aliev ZS, Babanly MB, Kokh KA, Tereshchenko OE, Chulkov EV, Schneider J, Kirschner J. Tuning the Dirac point position in Bi(2)Se(3)(0001) via surface carbon doping. Phys Rev Lett 2014; 113:116802. [PMID: 25259997 DOI: 10.1103/physrevlett.113.116802] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Indexed: 06/03/2023]
Abstract
Angular resolved photoemission spectroscopy in combination with ab initio calculations show that trace amounts of carbon doping of the Bi_{2}Se_{3} surface allows the controlled shift of the Dirac point within the bulk band gap. In contrast to expectation, no Rashba-split two-dimensional electron gas states appear. This unique electronic modification is related to surface structural modification characterized by an expansion of the top Se-Bi spacing of ≈11% as evidenced by surface x-ray diffraction. Our results provide new ways to tune the surface band structure of topological insulators.
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Affiliation(s)
- Sumalay Roy
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - C Tusche
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - M G Vergniory
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain
| | - T V Menshchikova
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Tomsk State University, 634050 Tomsk, Russia
| | - M M Otrokov
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain and Tomsk State University, 634050 Tomsk, Russia
| | | | - Z S Aliev
- Baku State University, General and Inorganic Chemistry Department, AZ1148 Baku, Azerbaijan
| | - M B Babanly
- Baku State University, General and Inorganic Chemistry Department, AZ1148 Baku, Azerbaijan
| | - K A Kokh
- Institute of Geology and Mineralogy SB RAS, 630090 Novosibirsk, Russia
| | - O E Tereshchenko
- Institute of Semiconductor Physics SB RAS, and Novosibirsk State University, 630090 Novosibirsk, Russia
| | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain and Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Spain
| | - J Schneider
- Department für Geowissenschaften Ludwig-Maximilians Universität München, D-80333 München, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
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Meyerheim HL, Ernst A, Mohseni K, Maznichenko IV, Henk J, Ostanin S, Jedrecy N, Klimenta F, Zegenhagen J, Schlueter C, Mertig I, Kirschner J. Tuning the structure of ultrathin BaTiO3 films on Me(001) (Me=Fe, Pd, Pt) surfaces. Phys Rev Lett 2013; 111:105501. [PMID: 25166678 DOI: 10.1103/physrevlett.111.105501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 03/01/2013] [Indexed: 06/03/2023]
Abstract
Using surface x-ray diffraction in combination with ab initio calculations, we demonstrate that the atomic structure of ultrathin BaTiO3 (BTO) films grown on Me(001) surfaces (Me=Fe, Pd, Pt) depends on subtle modifications of the interface chemical composition. A complete reversal of the surface termination from a BaO- [BTO on Fe(001)] to a TiO2-terminated film [BTO on Pt(001)] is observed which goes in parallel with the adsorption of submonolayer amounts of oxygen at metal hollow sites of the interface. Our results may suggest a new route to an overall control of both the surface and the interface geometry in BaTiO3/metal contacts.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - I V Maznichenko
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - J Henk
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - S Ostanin
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - N Jedrecy
- Institut des Nano Sciences de Paris, UPMC-Sorbonne Universités, CNRS-UMR7588, 75005 Paris, France
| | - F Klimenta
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - J Zegenhagen
- ESRF, Boîte Postale 220, F-38043 Grenoble Cedex, France
| | - C Schlueter
- ESRF, Boîte Postale 220, F-38043 Grenoble Cedex, France
| | - I Mertig
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
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Feng W, Meyerheim HL, Mohseni K, Brovko O, Stepanyuk VS, Jedrecy N, Felici R, Kirschner J. Misfit-induced modification of structure and magnetism in O/Fe(001)-p(1×1). Phys Rev Lett 2013; 110:235503. [PMID: 25167511 DOI: 10.1103/physrevlett.110.235503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/08/2013] [Indexed: 06/03/2023]
Abstract
The geometry of oxygen atoms in hollow sites of Fe nanoislands (⊘≈1-2 nm) on Fe(001) is modified by mesoscopic misfit-induced relaxations of the island atoms. Surface x-ray diffraction, scanning tunneling microscopy, and ab initio calculations indicate a 0.3 Å increased adsorption height [0.7 Å versus 0.4 Å in O/Fe(001)-p(1×1)] of O atoms going in parallel with a reduced Fe-Fe layer spacing inducing a reduction of the surface magnetic moment (2.85μ(B) versus 3.2μ(B)). Our results demonstrate the importance of the mesoscopic misfit for surface physical properties in general.
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Affiliation(s)
- W Feng
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - O Brovko
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - V S Stepanyuk
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - N Jedrecy
- Institut des Nano Sciences de Paris, UPMC-Sorbonne Universités, CNRS-UMR7588, 75005 Paris, France
| | - R Felici
- ESRF, B.P. 220, F-38043 Grenoble Cedex, France
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
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Meyerheim HL, Ernst A, Mohseni K, Maznichenko IV, Ostanin S, Klimenta F, Jedrecy N, Feng W, Mertig I, Felici R, Kirschner J. BaTiO3(001)-(2×1): surface structure and spin density. Phys Rev Lett 2012; 108:215502. [PMID: 23003278 DOI: 10.1103/physrevlett.108.215502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Indexed: 06/01/2023]
Abstract
Using surface x-ray diffraction and ab initio calculations we present a model of the BaTiO3(001)-(2×1) surface structure, which has not been considered so far. While the crystal is terminated by two TiO2 layers similarly to SrTiO3(001)-(2×1), we find that one out of two surface layer Ti-atoms resides in a tetragonal pyramidal oxygen environment. This peculiar geometry leads to a metallic and magnetic surface involving local magnetic moments up to 2μ(B) in magnitude located at surface Ti and O atoms. Our results are important for the understanding of the intrinsic surface metallicity of insulating oxides in general.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany.
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Thamankar R, Meyerheim HL, Ernst A, Ostanin S, Maznichenko IV, Soyka E, Mertig I, Kirschner J. Tilting, bending, and nonterminal sites in CO/Cu(001). Phys Rev Lett 2011; 106:106101. [PMID: 21469813 DOI: 10.1103/physrevlett.106.106101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Indexed: 05/30/2023]
Abstract
Using scanning tunneling microscopy experiments in combination with first-principles calculations we have studied the geometric structure of the compressed c(7sqrt(2) × sqrt(2)) antiphase domain structure of CO on Cu(001). We find direct evidence for structural relaxations involving an inhomogeneous CO environment characterized by molecular tilting, bending, and nonterminal sites. Our analysis solves the long-standing problem of the adsorption structure of the compressed phase and is important for understanding the physical properties of this fundamental adsorption system.
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Affiliation(s)
- R Thamankar
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Meyerheim HL, Klimenta F, Ernst A, Mohseni K, Ostanin S, Fechner M, Parihar S, Maznichenko IV, Mertig I, Kirschner J. Structural secrets of multiferroic interfaces. Phys Rev Lett 2011; 106:087203. [PMID: 21405597 DOI: 10.1103/physrevlett.106.087203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Indexed: 05/30/2023]
Abstract
We present an experimental and theoretical study of the geometric structure of ultrathin BaTiO(3) films grown on Fe(001). Surface x-ray diffraction reveals that the films are terminated by a BaO layer, while the TiO(2) layer is next to the top Fe layer. Cations in termination layers have incomplete oxygen shells inducing strong vertical relaxations. Onset of polarization is observed at a minimum thickness of two unit cells. Our findings are supported by first-principles calculations providing a quantitative insight into the multiferroic properties on the atomic scale.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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Meyerheim HL, Tonnerre JM, Przybylski M, Yildiz F, Fu XL, Bontempi E, Ramos A, Grenier S, Kirschner J. Spin structure in ultrathin fcc-Fe films on Cu(001). Acta Crystallogr A 2010. [DOI: 10.1107/s0108767310097771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Meyerheim HL, Tonnerre JM, Sandratskii L, Tolentino HCN, Przybylski M, Gabi Y, Yildiz F, Fu XL, Bontempi E, Grenier S, Kirschner J. New model for magnetism in ultrathin fcc Fe on Cu(001). Phys Rev Lett 2009; 103:267202. [PMID: 20366339 DOI: 10.1103/physrevlett.103.267202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 07/06/2009] [Indexed: 05/27/2023]
Abstract
Using soft-x-ray resonant magnetic scattering in combination with first-principles calculations for noncollinear magnetic configurations we present a new model of the magnetism in ultrathin fcc Fe films on Cu(001). We find the presence of blocks with robust magnetic structure, while the relative directions of the moments of different blocks are sensitive to the detailed atomic structure and temperature. The magnetic noncollinearity is directly demonstrated, which has not been possible so far.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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Meyerheim HL, Tusche C, Ernst A, Ostanin S, Maznichenko IV, Mohseni K, Jedrecy N, Zegenhagen J, Roy J, Mertig I, Kirschner J. Wurtzite-type CoO nanocrystals in ultrathin ZnCoO films. Phys Rev Lett 2009; 102:156102. [PMID: 19518654 DOI: 10.1103/physrevlett.102.156102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Indexed: 05/27/2023]
Abstract
Surface x-ray diffraction experiments reveal that, in cobalt-doped ZnO films two to five monolayers thick, Wurtzite-type CoO nanocrystals are coherently embedded within a hexagonal boron-nitride- (h-BN)-type ZnO matrix, supporting the model of a phase separation. First-principles calculations confirm that, in contrast with ZnO, the formation of h-BN-type CoO is unfavorable in the ultrathin film limit. Our results are important for understanding magnetic properties of transition metal-doped semiconductors in general.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle, Germany
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Meyerheim HL, Sander D, Negulyaev NN, Stepanyuk VS, Popescu R, Popa I, Kirschner J. Buried Ni/Cu(001) interface at the atomic scale. Phys Rev Lett 2008; 100:146101. [PMID: 18518052 DOI: 10.1103/physrevlett.100.146101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Indexed: 05/26/2023]
Abstract
We present a quantitative surface x-ray analysis of the buried Ni/Cu(001) interface structure after deposition of 3 and 5 monolayers of Ni at room temperature. Interface mixing is found where 27+/-10% of top layer Cu atoms are exchanged by Ni. Atomic scale simulations reveal a kinetic pathway for the Ni/Cu-exchange process and explain the observed limited degree of intermixing. A disperse distribution of Ni within the Cu surface with a preferential Ni-Ni separation of 3-4 nearest neighbor distances is determined.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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Mironets O, Meyerheim HL, Tusche C, Stepanyuk VS, Soyka E, Zschack P, Hong H, Jeutter N, Felici R, Kirschner J. Direct evidence for mesoscopic relaxations in cobalt nanoislands on Cu(001). Phys Rev Lett 2008; 100:096103. [PMID: 18352728 DOI: 10.1103/physrevlett.100.096103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Indexed: 05/26/2023]
Abstract
Surface x-ray diffraction in combination with scanning tunneling microscopy and molecular dynamics calculations provide first quantitative evidence for unusually large relaxations in nanometer-sized Co islands deposited on Cu(001) at 170 K. These lead to sharply reduced interatomic Co distances as low as 2.36 A as compared to bulk Co (2.51 A) involving low symmetry Co adsorption sites. Our results prove the validity of the concept of mesoscopic mismatch which governs the strain relaxation of nanosized islands in general.
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Affiliation(s)
- O Mironets
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Meyerheim HL, Sander D, Popescu R, Pan W, Popa I, Kirschner J. Surfactant-mediated growth revisited. Phys Rev Lett 2007; 99:116101. [PMID: 17930451 DOI: 10.1103/physrevlett.99.116101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Indexed: 05/25/2023]
Abstract
The x-ray structure analysis of the oxygen-surfactant-mediated growth of Ni on Cu(001) identifies up to 0.15 monolayers of oxygen in subsurface octahedral sites. This questions the validity of the general view that surfactant oxygen floats on top of the growing Ni film. Rather, the surfactant action is ascribed to an oxygen-enriched zone extending over the two topmost layers. Surface stress measurements support this finding. Our results have important implications for the microscopic understanding of surfactant-mediated growth and the change of the magnetic anisotropy of the Ni films.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Tusche C, Meyerheim HL, Kirschner J. Observation of depolarized ZnO(0001) monolayers: formation of unreconstructed planar sheets. Phys Rev Lett 2007; 99:026102. [PMID: 17678236 DOI: 10.1103/physrevlett.99.026102] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Indexed: 05/16/2023]
Abstract
A novel nonpolar structure of 2 monolayer (ML) thick ZnO(0001) films grown on Ag(111) has been revealed, using surface x-ray diffraction and scanning tunneling microscopy. Zn and O atoms are arranged in planar sheets like in the hexagonal boron-nitride prototype structure. The observed depolarization is accompanied by a significant lateral 1.6% expansion of the lattice parameter and a 3% reduced Zn-O bond length within the sheets. The nonpolar structure stabilizes an atomically flat surface morphology unseen for ZnO surfaces thus far. The transition to the bulk wurtzite structure occurs in the 3-4 ML coverage range, connected to considerable roughening.
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Affiliation(s)
- C Tusche
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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Tusche C, Meyerheim HL, Jedrecy N, Renaud G, Ernst A, Henk J, Bruno P, Kirschner J. Oxygen-induced symmetrization and structural coherency in Fe/MgO/Fe(001) magnetic tunnel junctions. Phys Rev Lett 2005; 95:176101. [PMID: 16383838 DOI: 10.1103/physrevlett.95.176101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Indexed: 05/05/2023]
Abstract
We present x-ray diffraction experiments and multiple-scattering calculations on the structure and transport properties of a Fe/MgO/Fe(001) magnetic tunnel junction (MTJ). Coherent growth of the top Fe electrode on the MgO spacer is observed only for Fe deposition in ambient oxygen atmosphere leading to a coherent and symmetric MTJ structure characterized by FeO layers at both interfaces. This goes in parallel with calculations indicating large positive tunnel magnetoresistance (TMR) values in such symmetric junctions. The results have important implications for achieving giant TMR values.
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Affiliation(s)
- C Tusche
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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Pentcheva R, Wendler F, Meyerheim HL, Moritz W, Jedrecy N, Scheffler M. Jahn-Teller stabilization of a "polar" metal oxide surface: Fe3O4(001). Phys Rev Lett 2005; 94:126101. [PMID: 15903940 DOI: 10.1103/physrevlett.94.126101] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Indexed: 05/02/2023]
Abstract
Using ab initio thermodynamics we compile a phase diagram for the surface of Fe3O4(001) as a function of temperature and oxygen pressures. A hitherto ignored polar termination with octahedral iron and oxygen forming a wavelike structure along the [110] direction is identified as the lowest energy configuration over a broad range of oxygen gas-phase conditions. This novel geometry is confirmed via x-ray diffraction analysis. The stabilization of the Fe3O4(001) surface goes together with dramatic changes in the electronic and magnetic properties, e.g., a half metal to metal transition.
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Affiliation(s)
- R Pentcheva
- Department of Earth and Environmental Sciences, University of Munich, Theresienstrasse 41, 80333 Munich, Germany.
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19
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Meyerheim HL, Sander D, Popescu R, Kirschner J, Robach O, Ferrer S. Spin reorientation and structural relaxation of atomic layers: pushing the limits of accuracy. Phys Rev Lett 2004; 93:156105. [PMID: 15524908 DOI: 10.1103/physrevlett.93.156105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Indexed: 05/24/2023]
Abstract
The correlation between an ad-layer-induced spin reorientation transition (SRT) and the ad-layer-induced structural relaxation is investigated by combined in situ surface x-ray diffraction and magneto-optical Kerr-effect experiments on Ni/Fe/Ni(111) layers on W(110). The Fe-induced SRT from in-plane to out-of-plane, and the SRT back to in-plane upon subsequent coverage by Ni, are each accompanied by a small lattice relaxation of at most 0.002 A. Such a small strain variation excludes a magnetoelasticity driven SRT, and we suggest the interface anisotropy as a possible driving force.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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20
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Meyerheim HL, Popescu R, Kirschner J, Jedrecy N, Sauvage-Simkin M, Heinrich B, Pinchaux R. Geometrical and compositional structure at metal-oxide interfaces: MgO on Fe(001). Phys Rev Lett 2001; 87:076102. [PMID: 11497904 DOI: 10.1103/physrevlett.87.076102] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2001] [Indexed: 05/23/2023]
Abstract
The geometric structure of MgO deposited on Fe(001) in ultrahigh vacuum by electron evaporation was determined in detail by using surface x-ray diffraction. In contrast to the common belief that MgO grows in direct contact on the Fe(001) substrate, we find an FeO interface layer between the substrate and the growing MgO structure which has not been considered thus far. This result opens new perspectives for the understanding of the Fe/MgO/Fe(001) interface and the tunneling magnetoresistance effect in general.
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Affiliation(s)
- H L Meyerheim
- Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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21
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Schulz H, Vogler H, Meyerheim HL, Moritz W. Defects in the reconstructed (111) and (−1−1−1) surfaces of InSb. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396081160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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22
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Schneider J, Meyerheim HL. High-temperature powder diffraction of pollucite up to 1073 K. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396085996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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23
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Meyerheim HL, Sawitzki R, Moritz W. X-ray structure analysis on alkali metals adsorbed on Ge(001)(2 x 1). Phys Rev B Condens Matter 1995; 52:16830-16844. [PMID: 9981090 DOI: 10.1103/physrevb.52.16830] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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24
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Pflanz S, Meyerheim HL, Moritz W, Robinson IK, Hoernis H, Conrad EH. Anisotropic roughening of vicinally miscut Ag(110): X-ray-reflection profile analysis using the domain-matrix method. Phys Rev B Condens Matter 1995; 52:2914-2926. [PMID: 9981363 DOI: 10.1103/physrevb.52.2914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wever J, Meyerheim HL, Jahns V, Moritz W, Schulz H. Structure determination of the 3×3 superstructure of the (111)-B-surface of InSb by three-dimensional X-ray data. Acta Crystallogr A 1993. [DOI: 10.1107/s0108767378091357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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27
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Meyerheim HL, Döbler U, Puschmann A. Preparation-dependent Co/Si(100) (2 x 1) interface growth: Spontaneous silicide formation versus interstitial-site mechanism. Phys Rev B Condens Matter 1991; 44:5738-5744. [PMID: 9998417 DOI: 10.1103/physrevb.44.5738] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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28
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Meyerheim HL, Döbler U, Puschmann A, Baberschke K. Amorphous molybdenum silicide layers and Mo/Si(100) interface growth: Local structure and preparation dependence. Phys Rev B Condens Matter 1990; 41:5871-5880. [PMID: 9994470 DOI: 10.1103/physrevb.41.5871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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