Polaronic Hole Localization and Multiple Hole Binding of Acceptors in Oxide Wide-Gap Semiconductors

By S. Lany, Alex Zunger. 2009

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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 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.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/4871f39685e4a89e28a97c069503a78d2f6b1f0a