@article{18589,
  abstract     = {{For the calculation of neutral excitations, time-dependent density functional theory (TDDFT) is an exact reformulation of the many-body time-dependent Schrödinger equation, based on knowledge of the density instead of the many-body wavefunction. The density can be determined in an efficient scheme by solving one-particle non-interacting Schrödinger equations—the Kohn–Sham equations. The complication of the problem is hidden in the—unknown—time-dependent exchange and correlation potential that appears in the Kohn–Sham equations and for which it is essential to find good approximations. Many approximations have been suggested and tested for finite systems, where even the very simple adiabatic local-density approximation (ALDA) has often proved to be successful. In the case of solids, ALDA fails to reproduce optical absorption spectra, which are instead well described by solving the Bethe–Salpeter equation of many-body perturbation theory (MBPT). On the other hand, ALDA can lead to excellent results for loss functions (at vanishing and finite momentum transfer). In view of this and thanks to recent successful developments of improved linear-response kernels derived from MBPT, TDDFT is today considered a promising alternative to MBPT for the calculation of electronic spectra, even for solids. After reviewing the fundamentals of TDDFT within linear response, we discuss different approaches and a variety of applications to extended systems.}},
  author       = {{Botti, Silvana and Schindlmayr, Arno and Del Sole, Rodolfo and Reining, Lucia}},
  issn         = {{1361-6633}},
  journal      = {{Reports on Progress in Physics}},
  number       = {{3}},
  pages        = {{357--407}},
  publisher    = {{IOP Publishing}},
  title        = {{{Time-dependent density-functional theory for extended systems}}},
  doi          = {{10.1088/0034-4885/70/3/r02}},
  volume       = {{70}},
  year         = {{2007}},
}

@article{18591,
  abstract     = {{Using density-functional theory, we investigate the stability of the half-metallic ground state of magnetite under different strain conditions. The effects of volume relaxation and internal degrees of freedom are fully taken into account. For hydrostatic compression, planar strain in the (001) plane and uniaxial strain along the [001] direction, we derive quantitative limits beyond which magnetite becomes metallic. As a major new result, we identify the bond length between the octahedrally coordinated iron atoms and their neighbouring oxygen atoms as the main characteristic parameter, and we show that the transition occurs if external strain reduces this interatomic distance from 2.06 Å in equilibrium to below a critical value of 1.99 Å. Based on this criterion, we also argue that planar strain due to epitaxial growth does not lead to a metallic state for magnetite films grown on (111)-oriented substrates.}},
  author       = {{Friák, Martin and Schindlmayr, Arno and Scheffler, Matthias}},
  issn         = {{1361-6633}},
  journal      = {{New Journal of Physics}},
  number       = {{1}},
  publisher    = {{IOP Publishing and Deutsche Physikalische Gesellschaft}},
  title        = {{{Ab initio study of the half-metal to metal transition in strained magnetite}}},
  doi          = {{10.1088/1367-2630/9/1/005}},
  volume       = {{9}},
  year         = {{2007}},
}