Dynamical mean field approach for non-collinear doped antiferromagnets
Abstract
We have generalized a dynamical mean field approach in the iterative perturbation scheme (H.Kajueter, G.Kotliar, Phys.Rev.Lett.77,131 (1996)) to study the electronic structure of non-collinear magnetic states. A local approximation for the exact self-energy in d=∞ is found to be a very convenient approximation for spin-spiral magnetic configurations for real 2d- and 3d-lattices. We investigate a doped 2d-antiferromagnet in the one-band Hubbard model and show that the antiferromagnetic (AFM) state is unstable towards the formation of a spin spiral configuration. The quasiparticle peak (in the density of states) agrees well with the quantum Monte Carlo calculations. As the non-doped AFM insulator is unstable in this approach, we argue that instead of the Iterative Perturbation Theory, a more realistic description for magnetic systems is obtained with a transverse and longitudinal spin fluctuation approach which includes the Hartree-Fock terms in the ''bath`` Green-function. In this case both the AFM density of states with the spin-polaron peaks, and the doped spin-spiral state are in a good qualitative agreement with quantum Monte Carlo calculations. We discuss the possibilities of a first-principle LDA generalization of this approach.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.S1405F