Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2000-03-04
Physics
Condensed Matter
Strongly Correlated Electrons
23 pages, Revtex, with 15 figures embedded in the text. Submitted to Phys. Rev. B
Scientific paper
10.1103/PhysRevB.62.9432
The main properties of realistic models for manganites are studied using analytic mean-field approximations and computational numerical methods, focusing on the two-orbital model with electrons interacting through Jahn-Teller (JT) phonons and/or Coulombic repulsions. Analyzing the model including both interactions by the combination of the mean-field approximation and the exact diagonalization method, it is argued that the spin-charge-orbital structure in the insulating phase of the purely JT-phononic model is not qualitatively changed by the inclusion of the Coulomb interactions. As an important application of the present mean-field approximation, the CE-type AFM state, the charge-stacked structure along the z-axis, and the (3x^2-r^2)/(3y^2-r^2)-type orbital ordering are successfully reproduced based on the JT-phononic model for the half-doped manganite. Topological arguments and the relevance of the Heisenberg exchange among localized t_{\rm 2g} spins explains why the nearest-neighbor Coulomb interaction does not destroy the charge stacking structure. It is also verified that the phase-separation tendency is observed both in purely JT-phononic and purely Coulombic models in the vicinity of the hole undoped region, as long as realistic hopping matrices are used. This highlights the qualitative similarities of both approaches, and the relevance of mixed-phase tendencies in the context of manganites. In addition, the rich and complex phase diagram of the two-orbital Coulombic model in one dimension is presented. Our results provide robust evidence that Coulombic and JT-phononic approaches to manganites are not qualitatively different ways to carry out theoretical calculations, but they share a variety of common features.
Dagotto Elbio
Hotta Takashi
Malvezzi Andre Luiz
No associations
LandOfFree
Charge-orbital ordering and phase-separation in the two-orbital model for manganites: Roles of Jahn-Teller phononic and Coulombic interactions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Charge-orbital ordering and phase-separation in the two-orbital model for manganites: Roles of Jahn-Teller phononic and Coulombic interactions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Charge-orbital ordering and phase-separation in the two-orbital model for manganites: Roles of Jahn-Teller phononic and Coulombic interactions will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-448637