Electric-field–induced electron density response of GaAs and ZnSe
Institut für Physik, Universität Potsdam - D-14469 Potsdam, Germany
Accepted: 28 October 1998
The response of the electron densities of GaAs and ZnSe to an external electric field was probed by measuring the variation of the integral intensity of several weak X-ray structure factors due to a field parallel to [1 1 1]. In the range we found a nearly linear dependence of the relative intensity variation on E for low indexed reflections (2 2 2, 0 6 0) and an additional E2-dependence for higher-indexed ones (4 4 2, 6 6 6). The results are interpreted in terms of a bond-charge model. The linear effect can be interpreted by the redistribution of valence charges from bonds parallel to E into bonds lying oblique (bond-charge transfer) whereas the origin of the non-linear effect is still unclear. After the exclusion of lattice effects (piezo-electric effect, internal strain) it ought to be allocated to a charge density response of the core region.
PACS: 61.10.-i – X-ray diffraction and scattering / 61.50.Lt – Crystal binding; cohesive energy / 71.20.Nr – Semiconductor compounds
© EDP Sciences, 1998