Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 28: FV-internes Symposium ”Theoretical Modeling of Materials with Correlated Electrons”

TT 28.3: Fachvortrag

Donnerstag, 11. März 2004, 14:50–15:15, H20

How Chemistry Controls Electron Localization in 3d¹ Perovskites — •O. K. Andersen — Max-Planck Institute for Solid State Research, D-70506 Stuttgart

A current route to describing the physical properties of real materials with strongly correlated electrons, is to derive a low-energy Hubbard Hamiltonian using Wannier-functions obtained by a density-functional calculation, and to solve it using the dynamical mean-field approximation. As an example, we consider the series of 3d¹ orthorhombic perovskites SrVO₃, CaVO ₃, LaTiO₃, and YTiO₃, in which an increasing tilting and rotation of the oxygen octahedron is accompanied by an increasing localization of the t_2g electron; the vanadates are mass-enhanced metals and the titanates Mott insulators. We show that cation covalency, rather than ion-sizes and JT-distortions, is the controlling mechanism.