English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The main properties of realistic models for manganites are studied usinganalytic mean-field approximations and computational numerical methods,focusing on the two-orbital model with electrons interacting throughJahn-Teller (JT) phonons and/or Coulombic repulsions. Analyzing the modelincluding both interactions by the combination of the mean-field approximationand the exact diagonalization method, it is argued that the spin-charge-orbitalstructure in the insulating phase of the purely JT-phononic model is notqualitatively changed by the inclusion of the Coulomb interactions. As animportant application of the present mean-field approximation, the CE-type AFMstate, the charge-stacked structure along the z-axis, and the(3x^2-r^2)/(3y^2-r^2)-type orbital ordering are successfully reproduced basedon the JT-phononic model for the half-doped manganite. Topological argumentsand the relevance of the Heisenberg exchange among localized t_{\rm 2g} spinsexplains why the nearest-neighbor Coulomb interaction does not destroy thecharge stacking structure. It is also verified that the phase-separationtendency is observed both in purely JT-phononic and purely Coulombic models inthe vicinity of the hole undoped region, as long as realistic hopping matricesare used. This highlights the qualitative similarities of both approaches, andthe relevance of mixed-phase tendencies in the context of manganites. Inaddition, the rich and complex phase diagram of the two-orbital Coulombic modelin one dimension is presented. Our results provide robust evidence thatCoulombic and JT-phononic approaches to manganites are not qualitativelydifferent ways to carry out theoretical calculations, but they share a varietyof common features.Comment: 23 pages, Revtex, with 15 figures embedded in the text. Submitted to  Phys. Rev.

Charge-orbital ordering and phase separation in the two-orbital model for manganites: Roles of Jahn-Teller phononic and Coulombic interactions