Theoretical study of the surface optical properties of clean and hydrogenated GaAs(110)

We present a calculation of the electronic and optical properties of the Ga As(110) : H surface performed within the first-principles density functiona l theory (DFT) in the local density approximation (LDA). The geometry and e lectronic structure are analyzed and compared with those of the clean surfa ce. The reflectance anisotropy spectrum and the differential reflectivity a re then computed. Taking into account the usual underestimation of the LDA gaps with respect to the experimental values, the comparison between our th eoretical spectra with available experimental reflectance data shows a sati sfactory agreement, allowing for the interpretation of the main structures in terms of electronic transitions.