We present a continuous-time Monte Carlo impurity solver for multiorbital impurity models which combines a strong-coupling hybridization expansion and a weak-coupling expansion in the Hund's coupling parameter J. This double-expansion approach allows to treat the dominant density-density interactions U within the efficient segment representation. We test the approach for a two-orbital model with static interactions, and then explain how the double expansion allows to simulate models with frequency dependent U(ω) and J(ω). The method is used to investigate spin-state transitions in a toy model for fullerides, with repulsive bare J but attractive screened J.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2015 Sept 10|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics