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Double exchange-driven spin pairing at the (001) surface of manganites

Alessio Filippetti·Warren E. Pickett
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Abstract

The (001) surface of La_{1-x}Ca_xMnO_3 system in various magnetic orderings is studied by first principle calculations. A general occurrence is that z^2 dangling bond charge -- which is ``invisible'' in the formal valence picture -- is promoted to the bulk gap/Fermi level region. This drives a double-exchange-like process that serves to align the surface Mn spin with its subsurface neighbor, regardless of the bulk magnetic order. For heavy doping, the locally ``ferromagnetic'' coupling is very strong and the moment enhanced by as much as 30% over the bulk value.

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Alessio Filippetti, Warren E. Pickett. 2000-01-25. Double exchange-driven spin pairing at the (001) surface of manganites. https://doi.org/10.1103/physrevb.62.11571

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