Abstract
We have studied the valence redistribution of V in trilayers, which are composed of only polar layers grown on (001) substrates, by core-level photoemission spectroscopy. We have found that the V valence is intermediate between and for thin cap layers, decreases with increasing cap-layer thickness, and finally recovers the bulk value of at unit-cell thickness. In order to interpret these results, we propose that the atomic reconstruction of the polar surface competes with the purely electronic V valence change so that the polar catastrophe is avoided at the cost of minimum energy.
- Received 8 June 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.236401
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