CIRCULAR-DICHROISM IN THE ANGULAR-DISTRIBUTION OF CORE PHOTOELECTRONSFROM SI(001) - A PHOTOELECTRON-DIFFRACTION ANALYSIS

Circular dichroism has by now been observed experimentally in the angu lar distributions of core photoelectrons from both adsorbed molecules and atoms in single-crystal substrates. Photoelectron-diffraction theo ry provides a general method for predicting and analyzing such effects , as we demonstrate here by applying it to such dichroism in a nonmagn etic single crystal: Si 2s and 2p emission from Si(001), as studied ex perimentally by Daimon et al. [Jpn. J. Appl. Phys. 32, L1480 (1993)]. Our calculations correctly predict the apparent rotation of certain ma jor diffraction features with right and left circularly polarized ligh t, and also provide a more quantitative approach to analyzing such dat a than a previously proposed model based upon considerations of forwar d-scattering effects in photoelectron excitation.