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Seiler A, Piekarz P, Ibrahimkutty S, Merkel DG, Waller O, Pradip R, Chumakov AI, Rüffer R, Baumbach T, Parlinski K, Fiederle M, Stankov S. Anomalous Lattice Dynamics of EuSi_{2} Nanoislands: Role of Interfaces Unveiled. PHYSICAL REVIEW LETTERS 2016; 117:276101. [PMID: 28084777 DOI: 10.1103/physrevlett.117.276101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 06/06/2023]
Abstract
We report a systematic lattice dynamics study of EuSi_{2} films and nanoislands by in situ nuclear inelastic scattering on ^{151}Eu and ab initio theory. The Eu-partial phonon density of states of the nanoislands exhibits anomalous excess of phonon states at low and high energies, not present in the bulk and at the EuSi_{2}(001) surface. We demonstrate that atomic vibrations along the island-substrate interface give rise to phonon states both at low and high energies, while atomic vibrations across the island-island interface result in localized high-energy phonon modes.
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Affiliation(s)
- A Seiler
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | - P Piekarz
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków, Poland
| | - S Ibrahimkutty
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | - D G Merkel
- ESRF-The European Synchrotron, F-38000 Grenoble, France
| | - O Waller
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | - R Pradip
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | - A I Chumakov
- ESRF-The European Synchrotron, F-38000 Grenoble, France
| | - R Rüffer
- ESRF-The European Synchrotron, F-38000 Grenoble, France
| | - T Baumbach
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
- ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
| | - K Parlinski
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków, Poland
| | - M Fiederle
- Freiburg Materials Research Center, University of Freiburg, D-79104 Freiburg, Germany
| | - S Stankov
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
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Stankov S, Yue YZ, Miglierini M, Sepiol B, Sergueev I, Chumakov AI, Hu L, Svec P, Rüffer R. Vibrational properties of nanograins and interfaces in nanocrystalline materials. PHYSICAL REVIEW LETTERS 2008; 100:235503. [PMID: 18643516 DOI: 10.1103/physrevlett.100.235503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 11/19/2007] [Indexed: 05/26/2023]
Abstract
The vibrational dynamics of nanocrystalline Fe(90)Zr(7)B(3) was studied at various phases of crystallization. The density of phonon states (DOS) of the nanograins was separated from that of the interfaces for a wide range of grain sizes and interface thicknesses. The DOS of the nanograins does not vary with their size and down to 2 nm grains still closely resembles that of the bulk. The anomalous enhancement of the phonon states at low and high energies originates from the DOS of the interfaces and scales linearly to their atomic fraction.
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Affiliation(s)
- S Stankov
- European Synchrotron Radiation Facility, BP220, Grenoble, France
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