Surface reconstructions of MnAs grown on GaAs(001)

During epitaxial growth of MnAs on GaAs(001) by molecular-beam epitaxy (MBE ) the surface exhibits various reconstructions depending on the growth cond itions. These reconstructions have been studied during growth by reflection high-energy electron diffraction (RHEED) and reflectance difference spectr oscopy (RDS). A feature sensitive to the surface structure was identified i n the RD spectra. After growth, the (1 x 2) and (1 x 1) reconstructions wer e cooled down to room temperature and imaged in ultrahigh vacuum with a con ventional scanning tunneling microscope (STM). Atomic-scale images of these surfaces are presented. (C) 2000 Elsevier Science B.V. All rights reserved .