Abstract
We study the origin of the temperature-induced Mott transition in . As a method we use the local-density mean-field theory. We show the following. (i) The Mott transition is driven by the change in structure from long to short -axis layered perovskite (); it occurs together with orbital order, which follows, rather than produces, the structural transition. (ii) In the metallic phase the orbital polarization is . (iii) In the insulating phase the lower energy orbital, , is full. (iv) The spin-flip and pair-hopping Coulomb terms reduce the effective masses in the metallic phase. Our results indicate that a similar scenario applies to (). In the metallic structures electrons are progressively transferred to the bands with increasing ; however, we find no orbital-selective Mott transition down to .
- Received 12 January 2010
DOI:https://doi.org/10.1103/PhysRevLett.104.226401
©2010 American Physical Society