Filters

2009 - 200912010 - 20121

More filters

2019 - 20202
Reset filters

Settings

DDC: 530 × Subject: Theoretical study ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Attosecond streaking in a nano-plasmonic field
    (Bristol : IOP, 2012) Kelkensberg, F.; Koenderink, A.F.; Vrakking, M.J.J.
    A theoretical study of the application of attosecond streaking spectroscopy to time-resolved studies of the plasmonic fields surrounding isolated, resonantly excited spherical nanoparticles is presented. A classification of the different regimes in attosecond streaking is proposed and identified in our results that are derived from Mie calculations of plasmon fields, coupled to classical electron trajectory simulations. It is shown that in an attosecond streaking experiment, the electrons are almost exclusively sensitive to the component of the field parallel to the direction in which they are detected. This allows one to probe the different components of the field individually by resolving the angle of emission of the electrons. Finally, simulations based on fields calculated by finite-difference time-domain (FDTD) are compared with the results obtained using Mie fields. The two are found to be in good agreement with each other, supporting the notion that FDTD methods can be used to reliably investigate non-spherical structures.
  • Thumbnail Image
    Item
    Electronic structure and magnetic properties of the spin-1/2 Heisenberg system CuSe2O5
    (Milton Park : Taylor & Francis, 2009) Janson, O.; Schnelle, W.; Schmidt, M.; Prots, Yu; Drechsler, S.-L.; Filatov, S.K.; Rosner, H.
    A microscopic magnetic model for the spin-1/2 Heisenberg chain compound CuSe2O5 is developed based on the results of a joint experimental and theoretical study. Magnetic susceptibility and specific heat data give evidence for quasi-one-dimensional (1D) magnetism with leading antiferromagnetic (AFM) couplings and an AFM ordering temperature of 17 K. For microscopic insight, full-potential density functional theory (DFT) calculations within the local density approximation (LDA) were performed. Using the resulting band structure, a consistent set of transfer integrals for an effective one-band tight-binding model was obtained. Electronic correlations were treated on a mean-field level starting from LDA (LSDA+U method) and on a model level (Hubbard model). With excellent agreement between experiment and theory, we find that only two couplings in CuSe2O5 are relevant: the nearest-neighbour intra-chain interaction of 165 K and a non-frustrated inter-chain (IC) coupling of 20 K. From a comparison with structurally related systems (Sr2Cu(PO4)2, Bi2CuO4), general implications for a magnetic ordering in presence of IC frustration are made.