Existence of a metallic ferromagnetic phase in models for undoped manganites

Article

关键词: JAHN-TELLER DISTORTION;    A-TYPE;    MAGNETIC-STRUCTURES;    LATTICE DISTORTION;    HARTREE-FOCK;    SPIN;    SEPARATION;    OXIDES;    LAMNO3;    STATES;   

DOI  :  10.1103/PhysRevB.67.104428

来源: SCIE

【 摘 要 】

The existence of a metal-insulator transition in the ferromagnetic state of models for undoped manganites is discussed here, using numerical techniques applied to the e(g)-orbital degenerate Hubbard model tightly coupled with Jahn-Teller distortions. The ground-state phase diagram is presented in the plane defined by the electron-phonon coupling lambda and Coulomb interaction u. In contrast to the standard one-band Hubbard model for cuprates, the metallic phase is found to exist for finite values of both lambda and u in the present e(g)-orbital Hubbard model even at half-filling, due to the Fermi-surface topology which is incompatible with the staggered orbital ordering concomitant to the insulating phase. Based on the present results, a possible scenario for the colossal magnetoresistive effect is discussed in undoped manganites.

【 授权许可】

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