Journal Article

PreJuSER-9075

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The boson peak in confined disordered system

Zorn, R.FZJ*

2010
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/10997  doi:10.1103/PhysRevB.81.054208

Abstract: The vibrational density of states (VDOS) of disordered systems shows a low-frequency excess, the so-called boson peak. Experiments show a change in the shape of the boson peak when the systems are spatially confined. Depending on the type of confinement (hard or soft) the low-frequency wing of the boson peak is either suppressed or enhanced. Here, a simple model, a crystalline system with disordered nearest-neighbor force constants, is studied with boundary conditions mimicking the confinement. The VDOS calculated by numerical diagonalization shows qualitatively the same confinement effect as the experiment. In this model, the effect is a consequence of modes of the bulk system being shifted up or down for hard and soft confinement, respectively. A simple rescaling procedure is suggested to convert the VDOS of the bulk into that of the confined system.

Keyword(s): J

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Neutronenstreuung (IFF-5)
2. Streumethoden (IFF-4)
3. JCNS (Jülich Centre for Neutron Science JCNS (JCNS) ; JCNS)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Appears in the scientific report 2010

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