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】
Free