Polaronic Hole Localization and Multiple Hole Binding of Acceptors in Oxide Wide-Gap Semiconductors
Acceptor-bound holes in oxides often localize asymmetrically at one out of several equivalent oxygen ligands. Whereas Hartree-Fock (HF) theory overly favors such symmetry-broken polaronic hole localization in oxides, standard local-density (LD) calculations suffer from spurious delocalization among several oxygen sites. These opposite biases originate from the opposite curvatures of the energy as a function of the fractional occupation number n, i.e., d{sup 2}E/dn{sup 2}<0 in HF and d{sup 2}E/dn{sup 2}>0 in LD. We recover the correct linear behavior, d{sup 2}E/dn{sup 2}=0, that removes the (de)localization bias by formulating a generalized Koopmans condition. The correct description of oxygen hole localization reveals that the cation-site nominal single acceptors in ZnO, In{sub 2}O{sub 3}, and SnO{sub 2} can bind multiple holes.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 975407
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 80, Issue 8, 2009
- Country of Publication:
- United States
- Language:
- English
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