Spin, charge, orbital and lattice degrees of freedom in quasi-cubic manganites: A brief review

The rich phase diagram of La1-xCaxMnO3 is the consequence of the interplay of spin, charge, orbital and lattice degrees of freedom, giving rise to several magnetic phases, Jahn-Teller distortions, spin-canting and phase separation, and orbital and charge order. Each Mn ion is in a mixed valent state of two magnetic configurations, Mn4+ and Mn3+. We study the phase diagram using mean-field slave bosons for the itinerant eg-electrons in two orbitals with excluded multiple occupancy of each site, Hund's rule interaction between the eg and t2g states and Jahn-Teller coupling of the eg orbitals to the lattice.