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Spiridis N, Zając M, Piekarz P, Chumakov AI, Freindl K, Goniakowski J, Kozioł-Rachwał A, Parliński K, Ślęzak M, Ślęzak T, Wdowik UD, Wilgocka-Ślęzak D, Korecki J. Phonons in Ultrathin Oxide Films: 2D to 3D Transition in FeO on Pt(111). Phys Rev Lett 2015; 115:186102. [PMID: 26565477 DOI: 10.1103/physrevlett.115.186102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 06/05/2023]
Abstract
The structural and magnetic properties of ultrathin FeO(111) films on Pt(111) with thicknesses from 1 to 16 monolayers (MLs) were studied using the nuclear inelastic scattering of synchrotron radiation. A distinct evolution of vibrational characteristics with thickness, revealed in the phonon density of states (PDOS), shows a textbook transition from 2D to 3D lattice dynamics. For the thinnest films of 1 and 2 ML, the low-energy part of the PDOS followed a linear ∝E dependence in energy that is characteristic for two-dimensional systems. This dependence gradually transforms with thickness to the bulk ∝E^{2} relationship. Density-functional theory phonon calculations perfectly reproduced the measured 1-ML PDOS within a simple model of a pseudomorphic FeO/Pt(111) interface. The calculations show that the 2D PDOS character is due to a weak coupling of the FeO film to the Pt(111) substrate. The evolution of the vibrational properties with an increasing thickness is closely related to a transient long-range magnetic order and stabilization of an unusual structural phase.
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Affiliation(s)
- N Spiridis
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland
| | - M Zając
- European Synchrotron Radiation Facility (ESRF), P.O. Box 220, F-38043 Grenoble, France
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
| | - P Piekarz
- Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - A I Chumakov
- European Synchrotron Radiation Facility (ESRF), P.O. Box 220, F-38043 Grenoble, France
| | - K Freindl
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland
| | - J Goniakowski
- Sorbonne Universités, UPMC Université Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005, Paris, France
| | - A Kozioł-Rachwał
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
| | - K Parliński
- Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - M Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
| | - T Ślęzak
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
| | - U D Wdowik
- Institute of Technology, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków, Poland
| | - D Wilgocka-Ślęzak
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland
| | - J Korecki
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
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Chumakov AI, Monaco G, Monaco A, Crichton WA, Bosak A, Rüffer R, Meyer A, Kargl F, Comez L, Fioretto D, Giefers H, Roitsch S, Wortmann G, Manghnani MH, Hushur A, Williams Q, Balogh J, Parliński K, Jochym P, Piekarz P. Equivalence of the boson peak in glasses to the transverse acoustic van Hove singularity in crystals. Phys Rev Lett 2011; 106:225501. [PMID: 21702612 DOI: 10.1103/physrevlett.106.225501] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Indexed: 05/31/2023]
Abstract
We compare the atomic dynamics of the glass to that of the relevant crystal. In the spectra of inelastic scattering, the boson peak of the glass appears higher than the transverse acoustic (TA) singularity of the crystal. However, the density of states shows that they have the same number of states. Increasing pressure causes the transformation of the boson peak of the glass towards the TA singularity of the crystal. Once corrected for the difference in the elastic medium, the boson peak matches the TA singularity in energy and height. This suggests the identical nature of the two features.
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Affiliation(s)
- A I Chumakov
- European Synchrotron Radiation Facility, Grenoble, France.
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Stankov S, Röhlsberger R, Slezak T, Sladecek M, Sepiol B, Vogl G, Chumakov AI, Rüffer R, Spiridis N, Łazewski J, Parliński K, Korecki J. Phonons in iron: from the bulk to an epitaxial monolayer. Phys Rev Lett 2007; 99:185501. [PMID: 17995420 DOI: 10.1103/physrevlett.99.185501] [Citation(s) in RCA: 4] [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: 06/04/2007] [Revised: 08/13/2007] [Indexed: 05/25/2023]
Abstract
The confinement of materials in low-dimensional structures has significant impact on propagating excitations like phonons. Using the isotope-specific 57Fe nuclear resonant vibrational spectroscopy we were able to determine elastic and thermodynamic properties of ultrathin Fe films on W(110). With decreasing thickness one observes a significant increase of the mean atomic displacement that goes along with an enhancement of vibrational modes at low energies as compared to the bulk. The analysis reveals that these deviations result from atomic vibrations of the single atomic layers at the two boundaries of the film, while the atoms inside the films vibrate almost bulklike.
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Affiliation(s)
- S Stankov
- European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble Cedex, France
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Jakób W, Janik J, Janik J, Bajorek A, Parliński K, Sudnik-Hrynkiewicz M. Molecular dynamics study by the neutron inelastic scattering method. ACTA ACUST UNITED AC 1967. [DOI: 10.1016/0031-8914(67)90118-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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