Zeitschriftenaufsätze

Schwieger, Stephan; Kienert, Jochen; Nolting, Wolfgang
Temperature dependence of interlayer exchange coupling: spin waves versus spacer effects. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 71 (2005), 17, S. 174441, insges. 9 S.

There are different mechanisms proposed to be responsible for the temperature dependence of the interlayer exchange coupling, namely, a smearing out of the spacer or interface Fermi surface and excitations and interactions of spin waves. We propose a possibility to separate both effects by calculating the excitation spectrum of an extended Heisenberg model and connecting the results with ferromagnetic resonance (FMR) experiments. To solve the Heisenberg model we use an approximation that was shown to yield excellent results. In this paper the main idea of this procedure is explained and a detailed investigation of the spin-wave contribution to the temperature dependence of FMR resonance frequencies and fields is carried out.

http://dx.doi.org/10.1103/PhysRevB.71.174441

Cimalla, Volker; Ecke, Gernot; Niebelschütz, Merten; Ambacher, Oliver; Goldhahn, Rüdiger; Lu, Hai; Schaff, William J.
Surface conductivity of epitaxial InN. - In: Physica status solidi, ISSN 1610-1642, Bd. 2 (2005), 7, S. 2254-2257

http://dx.doi.org/10.1002/pssc.200461448

Bunde, Armin; Dieterich, Wolfgang; Maaß, Philipp; Meyer, Martin
Ionic transport in disordered materials. - In: Diffusion in condensed matter, (2005), S. 813-856

Heinrichs, Stefan; Einax, Mario; Dieterich, Wolfgang; Maaß, Philipp; Majhofer, Andrzej
Surface diffusion and growth of alloy nanoclusters: a Monte Carlo study. - In: Diffusion fundamentals, ISSN 1862-4138, Bd. 2 (2005), 19.1-19.2, insges. 2 S.

http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195320

Beenken, Wichard J. D.; Lischka, Hans
Spectral broadening and diffusion by torsional motion in biphenyl. - In: The journal of chemical physics, ISSN 1089-7690, Bd. 123 (2005), 14, 144311, insges. 9 S.

We have studied biphenyl by time-dependent density-functional theory. In particular, we have analyzed the dependence of singlet excitation energies and transition dipoles on the torsional angle between the phenyl groups. The torsional spectrum has been computed quantum mechanically as well as semiclassically in order to understand how this influences the broadening of absorption and luminescence spectra. Our results are in best agreement with supersonic jet spectroscopy data, but also fit astonishingly well to spectra of biphenyl in condensed phase. Furthermore, we compare the torsional and vibrational relaxation and discuss qualitatively the general consequences for poly-para-phenylenes and related conjugated polymers as poly-thiophenes, considering, in particular, how side chains and solvents may affect the optical spectra.

https://doi.org/10.1063/1.2049269