Session V23: Focus Session: Charge/Orbital Ordering in Complex Oxides

11:15 AM–2:15 PM, Thursday, March 13, 2008
Morial Convention Center - 215

Sponsoring Units: DMP GMAG
Chair: Jeff Lynn, National Institute of Standards and Technology

Abstract ID: BAPS.2008.MAR.V23.9

Abstract: V23.00009 : Charge Ordering in Half-Doped Manganites: Small Charge Disproportion and Leading Mechanisms

1:15 PM–1:27 PM

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Authors:

  Dmitri Volja
    (Brookhaven National Laboratory)

  Wei-Guo Yin
    (Brookhaven National Laboratory)

  Wei Ku
    (Brookhaven National Laboratory)

The apparent contradiction between the recently observed weak charge disproportion and the traditional Mn$^{3+}$/Mn$^{4+}$ picture of the charge-orbital orders in half-doped manganites is resolved by a novel Wannier states analysis of the LDA$+U$ electronic structure. Strong electron itinerancy in this charge-transfer system significantly delocalizes the occupied low-energy ``Mn$^{3+}$'' Wannier states such that charge leaks into the Mn$^{4+}$-sites. Moreover, this feature is found to be generic in doped manganites. Based on a realistic effective Hamiltonian derived from first-principles calculations, we further quantify the leading mechanisms of the charge-orbital orders and find that both electron-lattice and electron-electron interactions are essential. \hspace{0.2 cm} {\it Preprint} arXiv:0704.1834.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.MAR.V23.9