Using inverse photoemission and we find that the bulk bands become discretized in highly perfect layer structures, such as Cu on fcc Co(100), Fe(100), Ag bcc Au Fe (100), Co Cu(100), Au(100). The electronic structure is analyzed framework of quantum-well states consisting Bloch functions modulated by an envelope function. wavelength function determined from \ensuremath{\lambda}/2 interferometer fringes produced periodic appearance with increasing film thickness. k conservation, one obtains...

Quantum well states are found at the Fermi level in Cu on Co(100) and Ag Fe(100) using inverse photoemission. They appear every 5.9\ifmmode\pm\else\textpm\fi{}0.5 layers Cu/Co(100), which agrees with 5.5- to 6-layer oscillation period of magnetic coupling Cu/Co(100) superlattices. For Ag/Fe(100) they connect minority-spin interface observed below ${\mathit{E}}_{\mathit{F}}$ previously, providing a channel through noble metal. These properties explained terms bulk band structure.

Contributing to the need for new graphene nanoribbon (GNR) structures that can be synthesized with atomic precision, we have designed a reactant renders chiral (3,1)-GNRs after multistep reaction including Ullmann coupling and cyclodehydrogenation. The synthesis has been successfully proven on different coinage metals, formation process, together fingerprints associated each step, studied by combining scanning tunneling microscopy, core-level spectroscopy, density functional calculations. In...

Light-matter interaction at the atomic scale rules fundamental phenomena such as photoemission and lasing while enabling basic everyday technologies, including photovoltaics optical communications. In this context, plasmons, collective electron oscillations in conducting materials, are important because they allow manipulation of fields nanoscale. The advent graphene other two-dimensional crystals has pushed plasmons down to genuinely dimensions, displaying appealing properties a large...

We present Auger-electron spectroscopy, low-energy electron diffraction, and $\ensuremath{\Delta}\ensuremath{\varphi}$ measurements of Cs adsorption on Si(100) subsequent oxidation the substrate. Our data provide evidence against complete charge transfer from alkali metal to Si as proposed recently. The amount Si${\mathrm{O}}_{2}$ produced by alkali-metal-promoted low-temperature silicon is found be strictly proportional alkali-metal coverage, which, together with measured changes in work...

Metal-organic interfaces based on copper-phthalocyanine monolayers are studied in dependence of the metal substrate (Au versus Cu), its symmetry [hexagonal (111) surfaces fourfold (100) surfaces], as well donor or acceptor semiconducting character associated with nonfluorinated perfluorinated molecules, respectively. Comparison properties these systematically varied metal-organic provides new insight into effect each previously mentioned parameters molecule-substrate interactions.

Increasingly high hopes are being placed on organic semiconductors for a variety of applications. Progress along these lines, however, requires the design and growth increasingly complex systems with well-defined structural electronic properties. These issues have been studied reviewed extensively in single-component layers, but focus is gradually shifting towards more functional multi-component assemblies such as donor-acceptor networks. blends show different properties from those...

The molecule/metal interface is the key element in charge injection devices. It can be generally defined by a monolayer-thick blend of donor and/or acceptor molecules contact with metal surface. Energy barriers for electron and hole are determined offset from HOMO (highest occupied) LUMO (lowest unoccupied) molecular levels this layer respect to Fermi level electrode. However, alignment not easy elucidate complex multicomponent, systems. We demonstrate that core-level photoemission...

Abstract Quantum dots are known to confine electrons within their structure. Whenever they periodically aggregate into arrays and cooperative interactions arise, novel quantum properties suitable for technological applications show up. Control over the potential barriers existing between neighboring is therefore essential alter mutual crosstalk. Here we that precise engineering of barrier width can be experimentally achieved on surfaces by a single atom substitution in haloaromatic compound,...

Surfaces of solid-state materials can be manipulated to fashion quantum dots and bespoke electronic properties. This review provides an overview the work done shape surface 2D electron gasses by means patterning with molecule-based networks formed via supramolecular self-assembly or atomistic manipulation protocols, giving rise distinct phenomena in regime. A vision applying engineering these techniques achieve control over states for many systems is presented.

STM images show that vicinal Au(788) surfaces are made up of a uniform array (111)-oriented terraces similar width $(\ensuremath{\sim}3.8\mathrm{nm})$. This uniformity makes it possible to study the electronic structure resulting step superlattice by angle-resolved photoemission. We for this terrace surface state appears be broken into one-dimensional quantum-well levels, indicating total electron confinement within terraces. The angular resolution allows probability density quantum well...

We present momentum-resolved inverse-photoemission data from Ge(100)2\ifmmode\times\else\texttimes\fi{}1, Si(100)2\ifmmode\times\else\texttimes\fi{}1, and GaAs(100)4\ifmmode\times\else\texttimes\fi{}2 surfaces. The bulk conduction bands of these three semiconductors are mapped along the \ensuremath{\Gamma}X direction. following critical points obtained (relative to valence-band maximum): For Ge, ${\mathrm{L}}_{3\mathrm{c}}$=4.4 eV ${\mathrm{L}}_{2\mathrm{c}}^{\ensuremath{'}}$=7.8 eV; for Si,...

We have studied the potassium- and cesium-promoted oxidation of Si(100)2\ifmmode\times\else\texttimes\fi{}1 with photoelectron Auger-electron spectroscopies in range submonolayer alkali-metal-atom coverages. The alkali-metal atoms efficiently promote silicon. Our results demonstrate that there are two oxygen species on surface during reaction: which bonded to potassium from very beginning process These detected core level O 1s valence-band photoemission spectra. Oxygen is transferred K Si,...

Surface chemistry and catalysis studies could significantly gain from the systematic variation of surface active sites, tested under very same conditions. Curved crystals are excellent platforms to perform such systematics, which may in turn allow better resolve fundamental properties reveal new phenomena. This is demonstrated here for carbon monoxide/platinum system. We curve a platinum crystal around high-symmetry (111) direction carry out photoemission scans on top. renders spatial...

Surface confined dehalogenation reactions are versatile bottom-up approaches for the synthesis of carbon-based nanostructures with predefined chemical properties. However, devices generally requiring low conductivity substrates, potential applications so far severely hampered by necessity a metallic surface to catalyze reactions. In this work we report ordered arrays poly(p-phenylene) chains on semiconducting TiO2(110) via dehalogenative homocoupling 4,4"-dibromoterphenyl precursors. The...

We investigate the chemical interaction of carbon monoxide (CO) and oxygen (O2) with kink atoms on steps platinum crystal surfaces using a specially designed Pt curved sample. aim at describing fundamental stages CO oxidation reaction, i.e., CO-covered/poisoned stage O-covered/active stage, poorly known kinked facets by probing uptake/saturation O2 saturation, respectively. Based systematic analysis that surface allows, high-resolution X-ray photoemission, diversity terrace step/kink species...

The periodic herringbone reconstruction on the surface of Au(111) consists alternating face-centered-cubic (fcc) and hexagonal-closed-packed (hcp) sites separated by dislocation lines elbows. This well-known arrangement acts as an...

Electrons at noble metal surfaces can be confined within terraces leading to one-dimensional surface states. These studied with angle-resolved photoemission from vicinal regular arrays of (111)-oriented terraces. Here we show the case Au(23 23 21), which is Au(111) and displays $L=56\mathrm{\AA{}}$ wide The state band appears broken up into three quantum well levels that match those infinite same width L. Their parallel momentum dependent intensity allows mapping probability density wave...

Vicinal noble metal surfaces with regular arrays of steps and terraces are very convenient model systems to test the electronic properties lateral nanostructures. Using angle-resolved photoemission synchrotron radiation we thoroughly characterize states wavefunctions in a variety vicinal Cu(111) Au(111) surfaces. By tuning terrace width, can observe fundamental transition from non-interacting nano-objects (terraces), where electron confined, coupling between terraces, which leads superlattice states.

The initial state and final contributions to the core level shift are separated by comparing shifts of occupied unoccupied Gd 4f levels, which exhibit with equal signs opposite signs. For clean Gd(0001) we find a surface −0.4 eV for both level. On other hand, 3–4 L oxygen is shifted + 1.0 respect bulk, −1.0 eV. Therefore, effect dominates at surface, while plays significant role oxidized surface. difference explained metallic versus dielectric screening.

The tunable properties of molecular materials place them among the favorites for a variety future generation devices. In addition, to maintain current trend miniaturization those devices, departure from present top-down production methods may soon be required and self-assembly appears most promising alternatives. On-surface synthesis unites promises self-assembly, with sturdiness covalently bonded structures: an ideal scenario applications. Following this idea, we report functional extended...

Recent advances in graphene-nanoribbon-based research have demonstrated the controlled synthesis of chiral graphene nanoribbons (chGNRs) with atomic precision using strategies on-surface chemistry. However, their electronic characterization, including typical figures merit like band gap or frontier band's effective mass, has not yet been reported. We provide a detailed characterization (3,1)-chGNRs on Au(111). The structure and epitaxy, as well ribbons, are analyzed by means scanning...

Understanding how specific atom sites on metal surfaces lower the energy barrier for chemical reactions is vital in catalysis. Studies simplified model systems have shown that atoms arranged as steps surface play an important role catalytic reactions, but a direct comparison of light-off temperature affected by orientation step has not yet been possible due to methodological constraints. Here we report situ spatially resolved measurements CO2 production over cylindrical-shaped Pd catalyst...