Cooperative jahn-teller coupling in the manganites
The cooperative Jahn-Teller coupling between the Mn e(g) electrons and the oxygen octahedral distortions in LaMnO3 is studied using ab initio density-functional calculations and tight-binding models. The linear and quadratic vibronic coupling parameters are calculated using density-functional methods. It is shown that the cooperative Jahn-Teller coupling, primarily due to the interoctahedral electron hopping (band structure term), leads to the ordering of the octahedral distortion and simultaneously to orbital ordering. The coupling results in a two-minima adiabatic potential surface in the solid, instead of the three-minima "Mexican-hat" surface for the isolated octahedron.
Popovic
Z
Department of Physics & Astronomy, University of Missouri, Columbia, Missouri 65211, USA.
Satpathy
S