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Orbital polarons and optical conductivity in doped manganites
Author(s) -
Bała J.
Publication year - 2005
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200460044
Subject(s) - polaron , condensed matter physics , optical conductivity , doping , conductivity , electrical resistivity and conductivity , ferromagnetism , paramagnetism , electron paramagnetic resonance , manganite , materials science , physics , chemistry , nuclear magnetic resonance , electron , quantum mechanics
Orbital polaron formation and the optical conductivity σ ( ω ) is investigated in the ferromagnetic and paramagnetic phases of doped ( x = 1/4) manganites. Using finite‐temperature diagonalization techniques for a realistic spin–orbital model we find the three‐site correlations specific for the orbital polarized state and the σ ( ω ) which is characterized by a broad spectrum with pronounced optical gap due to polaron formation. At small frequencies ( ω < t ) the conductivity is dominated by an incoherent spectrum with spectral weight decreasing with increasing temperature leading to an activated behavior in resistivity above T c . (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)