Electron-nuclear-double-resonance investigations of[Li]0and[Na

8Li+β-NMR in the Cubic Insulator MgO

“…The isotropic part of the hyperfine interaction with the hole spin is found to be −4.539 MHz [19]. The disappearance of anisotropy with increasing temperature was interpreted as a result of slow hopping of the hole among the neighbouring oxygen ions [18,19]. This picture was supported by several theoretical calculations [21,22,23] and is quite different from a symmetric localized state predicted more recently for Ca vacancies in CaO [24].…”

“…The holes are provided by high energy irradiation or by quenching [16]. EPR [15,17,18] and ENDOR [19] find a negative hyperfine field on the Li nucleus [20,21], and a significant anisotropy due to relaxation of the lattice with respect to the Li + -O − axis, breaking local cubic symmetry [15,19]. The isotropic part of the hyperfine interaction with the hole spin is found to be −4.539 MHz [19].…”

“…EPR [15,17,18] and ENDOR [19] find a negative hyperfine field on the Li nucleus [20,21], and a significant anisotropy due to relaxation of the lattice with respect to the Li + -O − axis, breaking local cubic symmetry [15,19]. The isotropic part of the hyperfine interaction with the hole spin is found to be −4.539 MHz [19]. The disappearance of anisotropy with increasing temperature was interpreted as a result of slow hopping of the hole among the neighbouring oxygen ions [18,19].…”

Defect complexes in Li-doped MgO

“…Using the Hartree-Fock (HF) method leads to localization of the Li valence electron on one nearest-neighbor O atom and as a consequence the distance between the Li atom and this O atom is elongated with respect to the equilibrium MgO bulk interatomic distance. Indication (but no rigorous proof) for this has also been found in electron paramagnetic resonance spectroscopy (EPR) and electron nuclear double resonance spectroscopy (ENDOR) experiments by Abraham et al [22,23]. In this work, three different starting geometries have been tested for the HSE06 geometry relaxation: (i) the relaxed symmetric PBE structure, (ii) a structure where the Li atom has approached one of its nearest-neighbor O atoms, according to the equilibrium structure found in Ref.…”

p-type semiconducting properties in lithium-doped MgO single crystals

“…[Li] 0 center (a substitutional Li + ion with a hole trapped in one of the six adjacent oxygen ions) [9,10,11]. This defect absorbs light at 1.8 eV [11].…”