4 research outputs found

    Effect of electron-lattice interaction on the phase separation in strongly correlated electron systems with two types of charge carriers

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    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

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    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.
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