Patel, J. R.Freeland, P. E.Hybertsen, M. S.Jacobson, D. C.Golovchenko, Jene2016-11-181987Patel, J. R., P. E. Freeland, M. S. Hybertsen, D. C. Jacobson, and J. A. Golovchenko. 1987. Location of Atoms in the First Monolayer of GaAs on Si. Physical Review Letters 59, no. 19: 2180-2183. doi:10.1103/physrevlett.59.2180.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:29407039The position of Ga and As atoms at monolayer coverages of heteroepitaxial GaAs on clean Si(111) have been measured by x-ray standing waves in UHV. Though both As and Ga are incident on the surface As atoms choose to occupy the upper half of the (111) double plane about 5% higher on the average, relative to the Si(111) d spacing, than the bulk silicon position. Ga atoms are exclusively located on the lower half of the (111) plane about 3% higher than the corresponding bulk positions.en-USJournal Article2016-11-1810.1103/PhysRevLett.59.2180