Resonant RHEED measurements of surface order onCu3Au(111)films

Abstract

We have determined the long-range-order parameter of the Cu 3 Au(111) surface using resonant reflection high-energy electron diffraction ͑RHEED͒. The samples were prepared by molecular-beam epitaxy. In the resonance condition, diffracted beams propagate along the surface and enhance the surface sensitivity of the probe. A comparison between the order parameters derived using different resonances establishes that the diffraction amplitudes determine the order parameter with quantitative precision. The order parameter is found to obey a power-law behavior as a function of temperature near the order-disorder transformation temperature T c . The critical exponent determined from the observations is ␤ϭ0.51Ϯ0.03. The result agrees well with the mean-field prediction ␤ϭ 1 2 , and this indication that critical fluctuations are not important is consistent with the fact that antiphase domains boundaries intersect the ͑111͒ surface. Experiments using disordered Cu 3 Au grown on an ordered crystal confirm that the effective probe depth of the resonant RHEED method is only 1.1 ML, so that the measured order parameter is relevant to the outer surface layers alone.

Effects of the stoichiometry and chemical order on the electronic structure and magnetic properties of Cr-Pt alloys probed by angular-resolved photoemission

“…26 A careful RHEED analysis ͑lattice parameters and symmetry͒ allows for the determination of the chemical order parameter. 27 A detailed growth study of CrPt 3 on SrTiO 3 will be published elsewhere. 26 The freshly prepared samples were transferred from the growth chamber into the connected analysis chamber without exposure to air.…”

First-principles calculations and XPS measurements of gold segregation at the Cu3Au(111) surface

“…8 Segregation can be studied by analyzing the energy balance at zero temperature. [9][10][11][12][13][14][15][16][17][18] Concerning specifically Au segregation to the surface, apparently there are conflicting results, both for experimental and theoretical work. Theoretical and experimental studies of Cu 3 Au(111) are scarce compared to those of the (100) surface, and they have mainly focused on the order-disorder transition.…”