Phase separation in doped systems with spin-state transitions

Abstract

Spin-state transitions, observed in many transition metal compounds containing Co${}^{3+}$ and Fe${}^{2+}$, may occur with the change of temperature, pressure, but also with doping, in which case the competition of single-site effects and kinetic energy of doped carriers can favor a change in the spin state. We consider this situation in a simple model, formally resembling that used for manganites in Phys. Rev. Lett. 95, 267210 (2005). Based on such a model, we predict the possibility of a jump-like change in the number of Co${}^{3+}$ ions undergoing spin-state transition caused by hole doping. A tendency to the electronic phase separation within a wide doping range is demonstrated. Phase diagrams with the regions of phase separation are constructed at different values of the characteristic parameters of the model.

9 pages, 5 figures, submitted to Phys. Rev. B

References in corpus (3)

• Spin-state polaron in lightly hole-doped LaCoO_3
• Doped orbitally-ordered systems: another case of phase separation
• Electron coherent and incoherent pairing instabilities in inhomogeneous bipartite and nonbipartite nanoclusters