Disproportionation and Metallization at Low-Spin to High-Spin Transition in Multiorbital Mott Systems
2011; American Physical Society; Volume: 106; Issue: 25 Linguagem: Inglês
10.1103/physrevlett.106.256401
ISSN1092-0145
Autores Tópico(s)Physics of Superconductivity and Magnetism
ResumoWe study the thermally driven spin state transition in a two-orbital Hubbard model with crystal-field splitting, which provides a minimal description of the physics of LaCoO(3). We employ the dynamical mean-field theory with a quantum Monte Carlo impurity solver. At intermediate temperatures we find a spin disproportionated phase characterized by a checkerboard order of sites with small and large spin moments. The high temperature transition from the disproportionated to a homogeneous phase is accompanied by a vanishing of the charge gap. With the increasing crystal-field splitting the temperature range of the disproportionated phase shrinks and eventually disappears completely.
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