Spectral function of highly-correlated electron systems

Final Report Abstract

We developed new tools for investigating the spectral function of realistic strongly correlated systems by combining the accurate of first-principle density-functional calculations in local density approximation (LDA) with complex many-body dynamical meanfield theory (DMFT). The general basis set of LDA+DMFT scheme based on the projector technique have been constructed. The reliable spectral function on real energy axes is investigate by means of LDA+DMFT calculations with numerically exact impurity solvers. For this purpose we generalized the efficient Lanczos formalism to the multiorbital case and non-zero temperature. We compare this scheme with standard Hirsch-Fye Quantum Monte-Carlo (QMC) formalism and with recently developed continuous-time QMC scheme. The stable results for spectral functions was obtained by the temperature Lanczos scheme since the CT-QMC scheme has problem of analytical continuation on the real axes. Results of spectral funuction calculations for different correlated systems were presented.

Publications

• Electron Correlations and the Minority-Spin Band Gap in Half-Metallic Heusler Alloys, Phys. Rev. Lett. 96,137203 (2006)
  L. Chioncel E. Arrigoni, M. I. Katsnelson, and A. I. Lichtenstein
  
• Spectral Function of Ferromagnetic 3d Metals: A Self-Consistent LSDA+DMFT Approach Combined with the One-Step Model of Photoemission, Phys. Rev Lett. 97, 227601 (2006)
  J. Braun, J. Minár, H. Ebert, M. I. Katsnelson, and A. I. Lichtenstein
  
• Theory of bulk and surface quasiparticle spectra for Fe, Co, and Ni, Phys. Rev. B 76,035107 (2007)
  A. Grechnev, I. Di Marco, M. I. Katsnelson, A. I. Lichtenstein, J. Wills, and O. Eriksson
  
• Double Counting in LDA+DMFT - The Example of NiO, J. Electron Spectroscopy Rel. Phenomena 75,11 2010
  M. Karolak, G. Ulm, T. O. Wehling, V. Mazurenko, A. Poteryaev, A. I. Lichtenstein