Search for broken symmetry in the Au(110) surface

Physical Review B, 2004

The free-electron like surface state on the (111) surface of gold shows a splitting into two parabolic subbands induced by the spin orbit interaction. Spin-resolved high-resolution photoemission experiments performed with a full three-dimensional spin polarimeter provide a detailed image of the resulting spin structure. In particular, spin-resolved momentum distribution maps show that the spin vector lies in the surface plane and is perpendicular to the momentum of the electrons as expected in a free-electron model. This method of measuring the spin structure of a two-dimensional electron gas allows the observation of the direction of electric fields as probed by the electrons. Although the energy splitting can only be understood as a consequence of strong atomic electric fields, no modulation of the spin direction due to these fields is detected.

Physical Review B, 2012

The clean surface of Au(100) presents a complex reconstruction characterized by a hexagonal topmost layer. We report an angle-resolved photoemission study of the electronic structure of this surface, including an analysis of the Fermi surface, combined with structural information from low-energy electron diffraction and scanning tunneling microscopy. In the complex Fermi surface map found, we identify different contributions from the bulk bands, from interface states located below the hexagonal topmost layer, and from the hexagonal topmost layer itself. The electronic states related to this layer exhibit quasi-one-dimensional character, in agreement with the chain aspect of the reconstructed layer, as demonstrated by their dispersion, periodicity, and reciprocal space location.

Journal of Electron Spectroscopy and Related Phenomena, 2004

The spin character of the splitting of the Shockley surface state on Au(111) is directly verified by measurements of the in-plane and out-of-plane spin polarizations in angle-resolved photoemission spectra. The two parabolic sub-bands that are momentum-shifted with respect to each other, reveal a distinct, opposite spin polarization that within the errors lies in the surface plane. The measured in-plane orientation of the spin vectors is consistent with the simple spin structure expected from a nearly-free-electron model, where the polarization axis is tangential to the Fermi surface of the surface state.

Surface Science, 1985

A new LEED intensity analysis of the reconstructed Au(110)-(1×2) surface results in a modification of the missing row model with considerable distortions which are at least three layers deep. The top layer spacing is contracted by about 20%, the second layer exhibits a lateral pairing displacement of 0.07 .~ and the third layer is buckled by 0.24 ,~. Distortions in deeper layers seem to be probable but have not been considered in this analysis. The inter-atomic distances in the distorted surface region show both an expansion and a contraction compared to the bulk value and range from 5% contraction to about 4% expansion.

Physical Review B, 2001

We present results from Inverse photoemission spectroscopy in the isochromat mode, with angular resolution, from the clean Au(113) surface. To identify the origin of the different resonances we have performed first principles calculations of the bulk band structure in the LMTO formalism. Using the particular characteristic of the spectrometer we have made a theoretical prediction of the bulk features dispersion as a function of parallel momentum, considering only energy and momentum conservation. Thus we have been able to unambiguously identify, from measured spectra various bulk derived resonances in addition to two surface resonances and a surface state in the [-110] and [33-2] directions respectively.

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1987

The computer code MARLOWE is used to study the scattering of low energy K+ ions from the reconstructed Au(ll0). A detailed trajectory analysis allows conclusions about the surface structure, i.e. the contraction of the surface.

Science, 1992

e-Journal of Surface Science and Nanotechnology, 2009

The growth as well as the compositional, electronic and structural properties of thin Au films deposited on a Pd(110) single crystal have been studied by means of ultraviolet photoelectron spectroscopy (UPS), photoemission of adsorbed xenon (PAX) and scanning tunneling microscopy (STM) as a function of film thickness (ranging from submonolayer amounts up to multilayers) and temperature. Our investigations indicate a Volmer-Weber growth mode of Au on Pd(110) at a deposition temperature of 300 K and below. As former studies already have shown, depositing Au amounts of less than 1 ML results in the formation of unreconstructed pseudomorphic Au islands. Above a critical thickness of 2 ML the formation of a (1 × 2) missing-row reconstruction typical for Au can be observed. This reconstructed Au bilayer is still in registry with Pd(110) and, thus, strained. Furthermore, our experiments show a strong temperature dependence of the surface morphology. Au multilayers prepared at 150 K, which are already quite flat, undergo a weak smoothening of the topmost atomic layer by annealing the sample up to 350 K. At a surface temperature of ∼ 450 K the diffusion of Au atoms into the bulk is initiated at the Au-Pd interface. Annealing a 3 ML thick Au film to 600 K finally results in the formation of an Au-Pd surface alloy, which is stable up to 900 K. A complete loss of Au from the surface can be detected at around 1050 K. Adsorption of CO as a probe molecule on the Au containing surfaces is only possible at low temperatures.

Physical Review B, 2002

Surface states at vicinal Au͑788͒ and Au͑322͒ have been investigated with angle-resolved photoemission and synchrotron radiation. Both surfaces are characterized by highly regular one-dimensional step arrays with relatively wide ͑ϳ3.9 Å͒ or narrow ͑ϳ1.3 Å͒ terraces in Au͑788͒ and Au͑322͒, respectively. Depending on the terrace size we observe that surface electrons behave in a completely different way. In Au͑788͒ terraces become one-dimensional, lateral quantum wells that confine surface electrons between adjacent steps. In Au͑322͒ surface electrons propagate across the step array forming two-dimensional superlattice bands. By tuning photon energy and angle we probe fundamental properties of the electron wave functions in both cases.

Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society

The epitaxial growth of Au on Ag(110) has been studied by scanning tunneling microscopy up to 8 ML. In the submonolayer range the results show that gold atoms are intermixed with the silver atoms in the top two layers. Above 1 ML a two‐dimensional fingerlike growth gives rise to anisotropic three‐dimensional islands of gold, which appear to be thermal equilibrium structures. Above 5 ML, the gold overlayer forms a (1×3) reconstruction which is manifested as double rows of atoms growing along [11¯0]. The development of this reconstruction is followed as a function of coverage.