Electron spin-resonance (ESR) and electron-nuclear double-resonance (ENDOR) study of the self-trapped hole in ZnWO₄ single crystals

Authors: Watterich A.¹; Kovcs L.¹; Wrz R.²; Schn F.²; Hofstaetter A.²; Scharmann A.²

Source: Journal of Physics: Condensed Matter, Volume 13, Number 7, 2001 , pp. 1595-1607(13)

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Abstract:

After x-ray irradiation at 20 K, an intrinsic O [iopmath latex="$^-$"] ^- [/iopmath] centre was identified by ESR and ENDOR spectroscopy as the self-trapped hole centre in ZnWO₄. Observation of one Zn and two strong W superhyperfine interactions allows us to distinguish between two possible trapping sites: the hole resides at the B-type oxygen position which has one Zn and two W nearest neighbours. Broadening of the ESR lines and averaging of the g-value is observed and explained as due to thermally activated hopping of the hole between two energetically equivalent oxygen positions. The activation energy of this reorientation is found to be [iopmath latex="$0.016\pm0.003$"] 0.016?0.003 [/iopmath] eV. The thermal decay of the intrinsic O [iopmath latex="$^-$"] ^- [/iopmath] centre, and its connection to thermoluminescence, has been studied; it shows that this centre cannot be the luminescence centre for the typical TL emission at [iopmath latex="${\sim}$"] ~ [/iopmath] 480 nm in ZnWO₄. This emission may be due to an intrinsic electron-type defect.

Language: English

Document Type: Miscellaneous

Affiliations: 1: Crystal Physics Laboratory, Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Konkoly-Thege M ?t 29-33, 1121 Budapest, Hungary 2: 1. Physics Institute, Justus-Liebig-University, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

Publication date: 2001-01-01