On the anisotropic optical response of Al(110)

Abstract

In a recent paper, good agreement was reported between the results of an ab initio full-potential linear augmented plane wave (FP-LAPW) calculation of the linear optical response of Al(1 1 0) and experimental measurements of the reflectance anisotropy. In the present work, our FP-LAPW calculations are extended to develop a microscopic picture of the anisotropic optical response at the Al(1 1 0) surface. Evidence for an anisotropic intraband transition (Drude) contribution in the infrared is presented, and the anisotropy is explained by considering the redistribution of charge that occurs when an Al(1 1 0) surface is created. The interband transitions that make the dominant contribution to the reflectance anisotropy at higher energy are identified, and the symmetries and the surface or bulk character of the initial and final states are determined. Changes in the relative energies and occupations of electronic states due to surface charge redistribution are a possible mechanism for the interband contribution to the reflectance anisotropy.