2007/05/31 by Claude Ederer, Chungwei Lin, Andrew J. Millis · 35 citations
Materials Science · Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Coupling (piping) #Density functional theory #Electronic and Structural Properties of Oxides #Hamiltonian (control theory) #Ion #Magnetic and transport properties of perovskites and related materials #Materials science #Mathematics #Octahedron #Physics #Quantum mechanics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.76.155105
published in Physical Review B 76(15) (American Physical Society) · replaced with final (published) version with improved presentation
openalex publication_date 2007/10/08 · arxiv created 2008/06/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The physics of manganites is often described within an effective two-band tight-binding (TB) model for the Mn eg electrons, which apart from the kinetic energy includes also a local ``Hund's rule'' coupling to the t2g core spin and a local coupling to the Jahn-Teller (JT) distortion of the oxygen octahedra. We test the validity of this model by comparing the energy dispersion calculated for the TB model with the full Kohn-Sham band structure calculated within the local spin-density approximation (LSDA) to density functional theory. We analyze the effect of magnetic order, JT distortions, and ``GdFeO3-type'' tilt rotations of the oxygen octahedra. We show that the hopping amplitudes are independent of magnetic order and JT distortions and that both effects can be described with a consistent set of model parameters if hopping between both nearest and next-nearest neighbors is taken into account. We determine a full set of model parameters from the density functional theory calculations, and we show that both JT distortions and Hund's rule coupling are required to obtain an insulating ground state within LSDA. Furthermore, our calculations show that the GdFeO3-type rotations of the oxygen octahedra lead to a substantial reduction of the hopping amplitudes but to no significant deviation from the simple TB model.