Atomic vibrational density of states of crystalline βFeSi2 and amorphous FeSi2 thin films

M. Walterfang, W. Keune, E. Schuster, A. T. Zayak, P. Entel, W. Sturhahn, T. S. Toellner, E. E. Alp, P. T. Jochym, and K. Parlinski
Phys. Rev. B 71, 035309 – Published 11 January 2005

Abstract

Nuclear resonant inelastic x-ray scattering of 14.4125keV synchrotron radiation was used to measure directly the partial vibrational density of states (VDOS), g(E), of crystalline βFe57Si2 and amorphous(a)Fe57Si2 thin films prepared by codeposition in ultrahigh vacuum. The structure of the samples was characterized by x-ray diffraction and Mössbauer spectroscopy. The VDOS of βFeSi2 extends up to Emax65meV and exhibits a strong peak at E36meV and weaker bands centered at about 25, 43, and 53meV. These characteristic features coincide with positions of prominent IR and Raman spectral lines reported in the literature. The measured VDOS shows good agremeent with the theoretical VDOS of crystalline βFeSi2 computed by using the density functional theory combined with the direct method. Contrary to the crystalline phase, the VDOS of aFeSi2 shows a broad peak at 30meV with little structure, and a deviation from Debye behavior at small excitation energies (<15meV). This is revealed as a peak in the reduced VDOS, g(E)E2, at Ebp10meV, which is interpreted as “boson peak.” Above the boson peak (30meVE60meV) g(E)E2 was observed to be approximately exp(EE0), with E0=7.4meV being close to Ebp.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
2 More
  • Received 7 August 2004

DOI:https://doi.org/10.1103/PhysRevB.71.035309

©2005 American Physical Society

Authors & Affiliations

M. Walterfang, W. Keune*, E. Schuster, A. T. Zayak, and P. Entel

  • Institute of Physics, University Duisburg-Essen, D-47048 Duisburg, Germany

W. Sturhahn, T. S. Toellner, and E. E. Alp

  • Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA

P. T. Jochym and K. Parlinski

  • Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow, Poland

  • *Author to whom correspondence should be addressed. Email address: Keune@uni-duisburg.de

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 71, Iss. 3 — 15 January 2005

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×