4 research outputs found
Effect of electron-lattice interaction on the phase separation in strongly correlated electron systems with two types of charge carriers
The effect of electron-lattice interaction is studied for a strongly
correlated electron system described by the two-band Hubbard model. A two-fold
effect of electron-lattice interaction is taken into account: in non-diagonal
terms, it changes the effective bandwidth, whereas in diagonal terms, it shifts
the positions of the bands and the chemical potential. It is shown that this
interaction significantly affects the doping range corresponding to the
electronic phase separation and can even lead to a jump-like transition between
states with different values of strains.Comment: 6 pages, 7 figures, submitted to Phys. Rev.
Doped orbitally-ordered systems: another case of phase separation
A possible mechanism of electronic phase separation in the systems with
orbital ordering is analyzed. We suggest a simple model taking into account an
interplay between the delocalization of charge carriers introduced by doping
and the cooperative ordering of local lattice distortions. The proposed
mechanism is quite similar to the double exchange usually invoked for
interpretation of phase separation in doped magnetic oxides like manganites,
but can be efficient even in the absence of any magnetic ordering. It is
demonstrated that the delocalized charge carriers favor the formation of
nanoscale inhomogeneities with the orbital structure different from that in the
undoped material. The directional character of orbitals leads to
inhomogeneities of different shapes and sizes.Comment: 7 pages, 4 figures, submitted to Phys. Rev.