title: Electron- or hole-assisted reactions of H defects in hydrogen-bonded KDP.
abstract: We present an ab initio study of the stability and defect reactions of neutral and charged H interstitial (H(i)) and H vacancy (H(v)) in KH2PO4 (KDP). We find that while there is no interaction between the neutral H(i) and the host, the addition of an electron leads to the ejection of a H host atom and the subsequent formation of an interstitial H2 molecule and a H(v). In sharp contrast, the addition of a hole results in the formation of a hydroxyl bond. Thus, H(i) in both charged states severs the H-bonded network. For the H(v), the addition of a hole leads to the formation of a peroxyl bridge. The neutral H(i) and the positively charged H(v) induce states in the gap. The results elucidate the underlying atomic mechanism for the defect reactions suggested by experiment.
authors.affiliation: Department of Physics, California State University, Northridge, California 91330-8268, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Liu
authors.forename: Nicholas
authors.initials: N
authors.lastname: Kioussis
authors.forename: S G
authors.initials: SG
authors.lastname: Demos
authors.forename: H B
authors.initials: HB
authors.lastname: Radousky