期刊论文详细信息
Multiplet effects in orbital and spin ordering phenomena: A hybridization-expansion quantum impurity solver study | |
Article | |
关键词: MEAN-FIELD THEORY; CORRELATED SYSTEMS; ELECTRONIC-STRUCTURE; BAND-STRUCTURE; TRANSITION; LAMNO3; LATIO3; MODELS; | |
DOI : 10.1103/PhysRevB.87.195141 | |
来源: SCIE |
【 摘 要 】
We use an efficient general hybridization-expansion continuous-time quantum Monte Carlo impurity solver (Krylov approach) to study orbital and spin ordering phenomena in strongly correlated systems within the local-density approximation plus dynamical mean-field theory approach. This allows us to include often-neglected interaction terms, to study models with large basis sets, to consider crystals with low-symmetry distortions, and to reach the very low experimental temperatures. We use this solver to study ordering phenomena in a selection of exemplary low-symmetry transition-metal oxides. For the rare-earth manganites, we show that including spin-flip and pair-hopping terms does not affect the Kugel-Khomskii orbital-order melting transition. For LaMnO3, we find that the commonly used two-band model with classical t(2g) spin gives a good description of the e(g) electrons when compared with the full five-orbital Hubbard model. Surprisingly not only the occupied orbital but also the eg spectral matrix is well reproduced. For the d(1) perovskites CaVO3 and YTiO3 we show that spin-flip and pair-hopping terms only weakly affect orbital fluctuations. Moreover, for the Mott insulator YTiO3 we can study the ferromagnetic polarization to very low temperatures, finding a transition temperature in remarkably good agreement with experiments.【 授权许可】
Free