| Bertrand Delamotte (Paris 6) |
|---|
| Non Perturbative Renormalization Group and the Kardar-Parisi-Zhang equation |
| The Non Perturbative Renormalization Group (NPRG) is by now a well
established and widly tested
method thanks to which several results unreachable by perturbative means
have been obtained
for systems either at or out of thermal equilibrium. We review the
method and show how NPRG
allows us to obtain the full phase diagram of the Kardar-Parisi-Zhang
equation in all dimensions
including the fixed point describing the strong coupling (rough phase)
with exponents in reasonable agreement
with numerical ones. |
| Bernard Derrida (ENS Paris) |
|---|
| Current fluctuations in non equilibrium systems |
| This talk will present a series of recent results on the fluctuations
of the current in non-equilibrium diffusive systems.
When the system is maintained in a non-equilibrium steady state by contact
with two reservoirs at unequal densities, the fluctuations of the current
have in general a non-Gaussian distribution which can be computed exactly
for diffusive systems [1,2,3].
For systems at equilibrium on a ring geometry, the cumulants of these
fluctuations take a universal scaling form which can be understood
by several theoretical approaches such as the Bethe ansatz or fluctuating
hydrodynamics [4].
Some recent results concerning non steady state initial conditions will
also be discussed [5].
[1] T. Bodineau, B. Derrida, Phys. Rev. Lett. 92, 180601 (2004)
Current fluctuations in non-equilibrium diffusive systems: an
additivity principle
[2] T. Bodineau, B. Derrida, Phys. Rev. E 72, 066110 (2005)
Distribution of current in non-equilibrium diffusive systems and phase
transitions
[3] T. Bodineau, B. Derrida, C. R. Physique 8, 540-555 (2007)
Cumulants and large deviations of the current through non-equilibrium
steady states
[4] C. Appert, B. Derrida, V. Lecomte, F. Van Wijland,
Phys. Rev. E 78, 021122 (2008)
Universal cumulants of the current in diffusive systems on a ring
[5] B. Derrida, A. Gerschenfeld, Current Fluctuations of the One
Dimensional Symmetric Simple Exclusion Process with Step Initial
Condition cond-mat/0902.2364 |
| Jean-Yves Fortin (Nancy Université) |
|---|
| Examples of a Grassmann technique applied to classical spin systems in 2D |
| In this talk, we will present an analytical method using Grassmann techniques to study the fermionic theory underlying general spin-S Ising models in two dimensions. The simplest case S=1/2 was understood a long time ago and is known to be equivalent to a massive free fermion theory possessing a second-order transition when the mass vanishes. Here we try to extend the method for general spin-S with the additional presence of a splitting field in the Hamiltonian. One of our motivation comes from the fact that there is little knowledge about the fermionic theory of such models and the relation to the free fermion theory of the S=1/2 2D Ising model. In particular we can show that the Blume-Capel model can be exactly mapped onto an interacting fermion model, with a bare mass depending on the value of the splitting field. The location of the points that make this bare mass vanish is very close to the numerical results found by Monte-Carlo method in the region of the second-order transition. The extension to spin-S models and a method to find the bare mass in general is presented, with an accuracy of less than 1% for the second-order transition lines in these models. The particular values of the transition points at zero splitting field are then compared to high and low-temperature expansions. |
| Rudolph Hilfer (Stuttgart) |
|---|
| Excess Wings in Glass Formers |
| Ferenc Iglói (KFKI, Budapest) |
|---|
| Nonequilibrium dynamics of fully frustrated Ising models at T=0 |
| We consider two fully frustrated Ising models: the antiferromagnetic triangular model in a field of strength, $h=H T k_B$, as well as
the Villain model on the square lattice. After a quench from a disordered initial state to $T=0$ we study the nonequilibrium dynamics
of both models by Monte Carlo simulations. In a finite system of linear size, $L$, we define and measure sample dependent relaxation time, $t_r$, which is the number of Monte Carlo steps until the energy is relaxed to the ground-state value. The distribution of $t_r$, in particular its mean value, $\langle t_r(L) \rangle$, is shown to obey the scaling
relation, $\langle t_r(L) \rangle \sim L^2 \ln(L/L_0)$, for both models. Scaling of the autocorrelation function of the antiferromagnetic triangular model is shown to involve logarithmic corrections, both at $H=0$ and at the field-induced Kosterlitz-Thouless transition, however the autocorrelation exponent is found to be $H$ dependent. |
| Sudhir Jain (Aston University) |
|---|
| Persistence in the Zero-Temperature Dynamics of the Q-State Potts Model |
| To follow |
| Wolfhard Janke (ITP Leipzig) |
|---|
| Fractals meet Fractals: Self-Avoiding Random Walks on Percolation Clusters (tentative) |
| We consider self-avoiding walks (SAWs) on the backbone of percolation
clusters in space dimensions $d=2, 3, 4$. Applying numerical simulations
based on the PERM chain-growth algorithm, we estimate the critical SAW
exponents and show that the whole multifractal spectrum of singularities
emerges in exploring the peculiarities of the model. We obtain estimates
for the set of critical exponents, that govern scaling laws of higher
moments of the distribution of percolation cluster sites visited by SAWs,
in a good correspondence with an appropriately summed field-theoretical
$\varepsilon=6-d$-expansion.
V. Blavatska and W. Janke,
{\em Scaling Behavior of Self-Avoiding Walks on Percolation Clusters\},
Europhys. Lett. {\bf 82}, 66006 (2008);
{\em Multifractality of Self-Avoiding Walks on Percolation Clusters\/},
Phys. Rev. Lett. {\bf 101}, 125701 (2008);
{\em Walking on Fractals: Diffusion and Self-Avoiding Walks on
Percolation Clusters\/},
J. Phys. {\bf A42}, 015001 (2009). |
| Dragi Karevski (Nancy Université) |
|---|
| Qantum Non-Equilibrium Steady States Induced by Repeated Interactions |
| We study the steady state properties of a finite XY chain coupled at its boundaries to quantum reservoirs. The reservoirs are made of free spins that interact one after the other with the boundary sites of the chain. We show that the dynamical equations governing the time evolution of the two-point correlation matrix are of Lindblad type in the continuous interaction limit. Under XY coupling with the reservoir spins, the steady state correlations are calculated exactly. It is shown that the relevant physical quantities characterizing completely the steady state are the magnetization profile and the associated current. Except at the boundary sites, the magnetization is equal to the average of the reservoirs magnetizations. The steady state current, proportional to the difference in the reservoirs magnetizations, shows a non-monotonous behavior with respect to the system-reservoir coupling strength, with an optimal current state for a finite value of the coupling. Finally, the steady state density matrix is shown to be of generalized Gibbs form. At small current linear irreversible thermodynamics predictions are recovered. |
| Ralph Kenna (Coventry University) |
|---|
| The Site-Diluted Ising Model in Two and Four Dimensions |
| The Ising model with uncorrelated, quenched random-site or random-bond disorder has been controversial in both two and four dimensions.
In these dimensions, the leading exponent $\alpha$, which characterizes the specific-heat critical behaviour, vanishes and
no Harris prediction for the consequences of quenched disorder can be made.
In the two-dimensional case, the controversy is between the strong universality hypothesis
which maintains that the leading critical exponents remain the same as in the pure case and the weak universality
hypothesis, which favours dilution-dependent leading critical exponents.
In the four-dimensional case unusual corrections to scaling characterize the model, and the precise nature of these corrections has been debated.
Here both versions of the model are subject to finite-size scaling analyses, paying special attention to the implications for multiplicative logarithmic corrections.
The analysis is fully supportive of the scaling relations for logarithmic corrections and of the strong scaling hypothesis in the 2D case.
Progress is also made in determining the correct 4D scenario. |
| Vivien Lecomte (Université de Genève) |
|---|
| Depinning transition for domain walls with an internal degree of freedom |
| We examine the dynamics of a domain wall subject to a pinning potential, in situations where the position of the wall is coupled to an internal degree of freedom (e.g. a spin phase, in magnetic domain walls). We investigate the corresponding depinning transition, which displays several novel features when compared to standard cases. At zero temperature, there exists a bistable regime for low forces, with a logarithmic behavior close to the transition. For weak pinning, there occurs a succession of bistable transitions corresponding to different modes of the phase evolution, separated by topological transitions. At finite temperature, using techniques from stochastic dynamical systems, we show that the force-velocity characteristics is non-monotonous, as an effect of the zero-temperature topological transitions. |
| Alexander Lopez (IVIC, Caracas) |
|---|
| Mach Zehnder spin interferometer for Rashba and Dresselhaus media: Exact solutions for perfect spin filtering |
| We address spin filtering through quantum spin interference in a medium that has both Rashba and Dresselhaus spin-orbit couplings. We propose an experimentally feasible electronic Mach Zehnder Interferometer and solve for the perfect spin filtering conditions. We find two broad solutions, one where filtering is achieved in the original incoming basis that is purely a non-Abelian solution, and the other where one needs a tilted axis to observe the polarized output spinor. Both solutions apply for arbitrary incoming polarization, and are only limited by the randomness of the incoming spinor state. |
| Ernesto Medina (IVIC, Caracas) |
|---|
| Chiral Electron Transport: Scattering Through Helical Potentials |
| We present a model for the transmission of spin-polarized electrons through oriented chiral molecules, where the chiral structure is represented by a helix. The scattering potential contains a confining term and a spin-orbit contribution that is responsible for the spin-dependent scattering of the electrons by the
molecular target. The differential scattering cross-section is calculated for right- and left-handed helices and for arbitrary electron spin polarizations. We apply our model to explain chiral effects in the intensity of photo-emitted polarized electrons transmitted through thin organic layers. These are
spin-active molecular interfaces that exhibit electron dichroism and a number of remarkable magnetic properties. In our model, differences in intensity are generated by the preferential transmission of electron beams whose polarization is oriented in the same direction as the sense of advance of the helix. |
| Cécile Monthus (CEA Saclay) |
|---|
| Dynamics of random systems : strong disorder renormalization approach |
| To understand the non-equilibrium dynamics of random systems, we will describe a strong disorder renormalization procedure in configuration space, that we define for any master equation with transitions rates $W ({\cal C} \to {\cal C}')$ between configurations. The idea is to eliminate iteratively the configuration with the highest exit rate $W_{out} ({\cal C})= \sum_{{\cal C}'} W ({\cal C} \to {\cal C}')$ to obtain renormalized transition rates between the remaining configurations. The multiplicative structure of the new generated transition rates suggests that, for a very broad class of disordered systems, the distribution of renormalized exit barriers defined as $B_{out} ({\cal C}) \equiv - \ln W_{out}({\cal C})$ will become broader and broader upon iteration, so that the strong disorder renormalization procedure should become asymptotically exact at large time scales. As an example of application, we have checked numerically this scenario for the non-equilibrium dynamics of a directed polymer in a two dimensional random medium. |
| Arnaud Ralko (Grenoble) |
|---|
| Emergence of Generic Mixed Phases in Rokshar-Kivelson Models |
| The phase diagram of Rokhsar-Kivelson models, which are used in fields such as superconductivity, frustrated magnetism, cold bosons, and the physics of Josephson junction arrays, is revisited. From an extended height effective theory, we show that one of two simple generic phase diagrams contains a mixed phase that interpolates continuously between columnar and plaquette states.
Applied to the square lattice frustrated Heisenberg antiferromagnet, we have extended the Rokhsar-Kivelson (RK) loop-expansion to derive a generalized Quantum Dimer Model containing only connected terms up to arbitrary order. Our results suggest that the Heisenberg model is a physical realization of such a mixed phase, in the parameter region of maximum frustration. |
| Christian von Ferber (Coventry) |
|---|
| Shapes of embedded networks |
| tba |
|
| Jose Avila (Soleil) |
|---|
| Electronic structure of advanced materials using spacially resolvec photoemission |
| Microscopy of photoemission SPEM (Scanning PhotoEmission Microscope) is a powerful characterization technique of heterogeneous systems using the photoelectric effect, i.e. the generation of electrons by a system subjected to an electromagnetic radiation. Contrary to the PEEM microscopy, where the image is obtained by collecting the photoelectrons through an electronic column of optics, the imagery here is generated by a simple nanometer sweeping of the samples and focusing the incident light. ANTARES is one of the first beamlines in Europe that is attempting to extend such demanding technique to the low energy domain, where the states of the valence band can be detected with high precision as well as their dispersions using angle resolved photoemission (ARPES). The objective is to be able to determine the electronic band structure and the Fermi surface together with the chemical shift core level of light elements of advanced materials with a nanometer spatial resolution. The possibility of achieving synchrotron light beams from a few tens of nm to some µm, makes possible the visualization of density of states, chemical heterogeneities likewise magnetic order distributions getting the cartography of the samples on the basis of contrast produced by the photoemission response. This setup is being outfitted with several absorption detectors in order to complementarily obtain, in situ, the imagery based on the absorption contract.
The SPEM microscope at ANTARES beamline will operate in two alternative modes, the imagery and the spectroscopy. In the first mode, the material will be monitored using a synchronized sweeping of the sample with regard to the focused beam, by simultaneously detecting photoelectrons with a given kinetic energy. The second mode allows the determination of the photoemission and absorption spectra at a selected nanometer portion of the sample. I will give several examples of Scanning X-Ray microscopic studies of a range of heterogeneous systems with applications mainly in corrosion, heterogeneous chemical and structural aggregates and massive systems as well as the growth of metals and characterization of catalysts. Finally, an overview of the utilization limits of the x-ray microscopes will be detailed together with the future developments based on the last generation of detectors and new focalization optics. |
| Silke Biermann (Ecole Polytechnique - Palaiseau) |
|---|
| Electronic structure of correlated materials: a dynamical mean field perspective |
| During the last years new methods for the description
of the electronic structure of correlated materials
have been developed. The combination of dynamical mean
field techniques with density functional theory ("LDA+DMFT")
allows for the calculation of electronic properties
of materials from first principles, taking into account
the effect of strong Coulomb interactions.
After a brief review of the theoretical aspects, we will
describe some recent advances on transition metal oxides
and f-electron materials. |
| Evgeny Chulkov (San Sebastian) |
|---|
| DECAY OF EXCITED ELECTRONS IN SURFACE STRUCTURES |
| Interaction between lattice and electron subsystems as well as interaction within each of these subsystems is crucial to understand mechanism of single-particle excitation dynamics, i.e. lifetime of excitations. The lifetime sets the duration of excitation and in combination with the velocity determines the mean free path, a measure of influence of the excitation. Interest to the study of excited particles dynamics is motivated by an important role that excited electrons and holes play in many processes, e.g. in energy and charge transfer in bulk materials, at surfaces, across interfaces, and at nanosystems.
In this presentation I discuss recent theoretical results on the decay of excited electrons and holes at clean metal surfaces, at single adatoms, at islands as well as at overlayers and free standing thin films. Different decay mechanisms and different kinds of interactions - elastic and inelastic electron-
electron (e-e) interaction as well as electron-phonon (e-ph) interaction - are analysed. E-ph decay channel is shown to be important for all systems considered. In the e-e decay channel the electron (hole) decay can be realized via creation of electron-hole pairs or plasmon excitation. Dimensionality effects in the lifetime of electrons and holes on metal surfaces and the role of screening and intra- (inter-) band transitions are also discussed. |
| Oliver Groening (Thun - Switzerland) |
|---|
| Electron Scattering in Carbon Nanotubes |
| Abstract_Groening |
| Bertrand Kierren (Nancy Université) |
|---|
| Electron confinement in nano resonators: life time investigation and coupling effects. |
| We will focus on the Shockley state confinement in quantum resonators. In the first part i will show that using original design, it is possible to built nano resonators with high reflection coefficient, making possible life time analysis. I will show that a Fermi liquid behaviour can be observed and electron/hole and electron/phonon contributions will be discussed. In te second part of the talk, i will present recent results of STS obtained in chlorine based quantum corrals. The study from single isolated corral to chain of multiple corrals will be presented. The possible coupling between quantum wells will be discussed. |
| Jorge Lobo Checa (Centre d'Investigaciò en Nanociè) |
|---|
| Surface state confinement imposed by a supramolecular porous network: Band formation from coupled quantum dots |
| The properties of crystalline solids can to a large extent be derived from the scale and dimensionality of periodic arrays of coupled quantum systems like atoms and molecules. Periodic quantum confinement in two dimensions has been elusive on surfaces mainly because of the challenge to produce regular nanopatterned structures capable of trapping electronic states. The practical implementation of this type of confinement will be shown by demonstrating that the two dimensional free electron gas of the Cu(111) surface state can be trapped within the pores of an organic nanoporous network. The confinement units can be regarded as a regular array of quantum dots. Moreover, a shallow dispersive electronic band structure is formed, which is indicative of electronic coupling between neighbouring pore states. |
| Konrad Matho (Institut Néel - Grenoble) |
|---|
| On kinks and waterfalls in ARPES |
| Angle resolved photoemission spectroscopy (ARPES) allows to reveal a regime change in the momentum dependence of low energy fermionic excitations, as the distance from the Fermi surface increases. From gentle dispersion crossovers in most systems, more accentuated "kinks" or even "waterfalls", i.e.: discontinuities as function of k - k_F, have been observed. They are attributed to the presence of strong correlations among the fermions or strong electron-lattice coupling. I shall present the simplest generic model for a complex selfenergy function that allows to classify such phenomena and analyse the ARPES data quantitatively. The main driving parameter is the ratio of coherent spectral weight over total low energy weight, including the incoherent part. Further, I shall discuss the influence of asymmetry between particle- and hole-like excitations and, time permitting, the evolution of "kinks" as function of temperature. |
| Claude Monney (Fribourg) |
|---|
| Temperature dependence of the exciton condensate phase in 1T-TiSe2 |
| At the temperature of 200K, the quasi-two-dimensional system 1T-TiSe2 undergoes a phase transition towards a charge density wave (CDW) phase, which is accompanied by a periodic lattice distortion (PLD) [1].
We propose the exciton condensate phase model as the purely electronic origin of the CDW phase of 1T-TiSe2 [2,3]. Measured angle-resolved photoemission spectroscopy data are compared with photoemission intensity maps generated by the spectral function within this model [4,5]. We also discuss features of the model which allow extracting from the experiment the temperature dependence of the corresponding order parameter. Finally, we show recent results on the coupling of the exciton condensate to the lattice, which demonstrate that the presence of condensed excitons are capable of producing the observed PLD.
References:
[1] F. J. Di Salvo et al.., Phys. Rev. B, 14 (4321), 1976
[2] D. Jérôme et al., Phys. Rev., 158 (462), 1967
[3] L.V. Keldysh et al., Sov. Phys. Solid State, 6 (2219), 1965
[4] H. Cercellier et al., Phys. Rev. Lett., 99 (146403), 2007
[5] C. Monney et al., Phys. Rev. B, 79 (045116), 2009 |
| Enrique Ortega (San Sebastian) |
|---|
| Investigating Shockley surface states in curved noble metal surfaces: interplay between structure and electronic states |
| Vicinal surfaces with periodic arrays of steps and terraces are among the simplest lateral nanostructures. They are useful as growth templates for self-assembled arrays of nanostructures, but also attractive playgrounds for testing the fundamental properties of electrons at one- or two-dimensional (1D or 2D) superlattices. The most studied case is that of vicinal noble metal surfaces, where repulsive scattering gives rise to a rich surface electronic structure and phenomena that depend on the terrace size (lattice constant) d. On the one hand, the Shockley-like surface state that characterizes these surfaces is observed to evolve from a quasi-1D state to a 2D band as a function of d. On the other hand, surface states are characterized by relatively large (15-40AA) Fermi wavelengths in noble metal surfaces, and hence may exhibit 1D Fermi surface nesting with reciprocal lattice vectors pi/d. In the latter case, the question arises whether a charge density wave (CDW)-like, structural/electronic interplay occurs, i.e., whether such Fermi surface nesting and subsequent Fermi gap opening triggers structural instabilities in the step superlattice.
We use curved crystals to investigate the evolution of surface states as a function of d, namely the miscut angle (alpha) in a single sample. In particular we utilize Au and Cu curved surfaces that cover a alpha=+-15° range of miscuts around the [111] direction (alpha=0°). The local structure is determined by Scanning Tunneling Microscopy (STM), whereas surface bands are mapped locally for each miscut angle by Angle Resolved Photoemission (ARPES) by scanning a 100 mum synchrotron light spot. |
| Stephane Pons (EPFL - Lausanne) |
|---|
| Titel Pons |
| Abstract Pons |
| Friedrich T Reinert (Wuerzburg) |
|---|
| Modifing the Rashba Splitting of Metallic Surface States |
| This talk will summarize recent experiments by photoemission spectroscopy (ARUPS) on metallic surfaces, that reveal a considerable Rashba splitting as a consequence of the changed local symmetry at the surface. The splitting is due to the spin-orbit coupling of the contributing electronic states and depends strongly on the atomic composition of the surface, as e.g. in a surface alloy. It shall be discussed, how these states depend on surface modifications as induced by electron doping, local geometry, or by the coverage with a dielectric overlayer. |
| Dimitri Roditchev (INSP - CNRS, Université Paris 6) |
|---|
| Ultimate Vortex Confinement |
| Authors: Tristan Cren, Denis Fokin, François Debontridder, Vincent Dubost and Dimitri Roditchev
We report a detailed Scanning Tunneling Spectroscopy (STS) study of a superconductor in a strong vortex confinement regime. This is achieved in a thin nano-island of Pb having a size D about
three times the coherence length, and a thickness h such that h<< D < |
| Stephano Rusponi (Lausanne) |
|---|
| XAS study of individual magnetic atoms on insulating substrates |
| Andres Santander (ESPCI - Paris) |
|---|
| Angle resolved electronic structure of electron-doped SrTiO3: new hints for old puzzles |
| SrTiO3 is considered the cornerstone of oxide electronics. It is often used as a substrate for thin-film growth of other transition-metal oxides, and is the preferred template to create novel 2D phases of electron matter at oxide interfaces. SrTiO3 is also a model system for strongly-correlated electron physics: upon electron-doping the Ti 3d band, it goes from a band insulator to a correlated metal, and turns into a Mott-Hubbard insulator when all the Sr is substituted by La. However, despite the technological and fundamental importance of this material, key questions as the precise experimental determination of its momentum-resolved band structure and Fermi surface remain unsolved. Indeed, the electronic structure near the Fermi level (EF) of doped SrTiO3 is not that of a doped band insulator: besides the appearance of coherent states at EF, a broad peak of incoherent states centred at about 1.3 eV forms in its band-gap. These in-gap states, obviously not explained by a rigid shift of the bands with increasing doping, are observed already at dopings as low as x ~ 0.05 (about 1 electron every 20 unit cells), where electron correlations are expected to be small. Thus, they cannot correspond either to precursors of the “lower Hubbard band” of the d1 insulator. The nature of these in-gap states has also been a long-standing puzzle in the physics of SrTiO3.
Using angle-resolved photoemission spectroscopy (ARPES) we have studied in detail the electronic structure of SrTiO3 doped with oxygen vacancies. We determined that the Fermi surface, centred at Gamma, is composed of a central spherical-like sheet surrounded by cigar-like sheets. We observed the degeneracy lift in the conduction band induced by the cubic-to-tetragonal transition occurring at 110°K. Furthermore, we observed that the in-gap states do not disperse, indicating that they originate from localized states, rather than from electron-correlations. |
| Wolf Dieter Schneider (Lausanne) |
|---|
| Spectroscopic manifestation of low dimensional physics: a local view |
| The interest in nanostructured materials, consisting of building blocks of a small number of atoms or molecules, arises from their promising new optic, catalytic, magnetic and electronic poperties, which are fundamentally different from their macroscopic bulk counterparts: small is different. Here we present selected examples from our laboratory, which elucidate local aspects of physics in low dimensions investigated by photoemission (PES) and by low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS): Kondo effect of supported magnetic adatoms [1-3], electronic properties (electron confinement, lifetimes of surface states and of quantum well states, supraconductivity) of ultrathin supported metal islands [4-8], self-assembly, melting and electronic structure of two-dimensional adatom superlattices stabilized by long-range electronic interactions [9-12], two-dimensional supramolecular self-assembly, chirality, and electronic structure of small organic molecules [13-17], inelastic tunneling processes leading to vibrational excitations of supported molecules[18] and to local fluorescence and phosphorescence [19-21] enabling chemical recognition at the molecular scale.
[1] F. Patthey. B. Delley, W. D. Schneider and Y. Baer, Phys. Rev. Lett. 55, 1518 (1985).
[2] J. Li, W.-D. Schneider, R. Berndt, B. Delley, Phys. Rev. Lett. 80, 2893 (1998).
[3] M. Ternes, A. J. Heinrich, and W.-D. Schneider, J. Phys.: Cond. Matter 21, 053001 (2009).
[4] F. Patthey and W.-D. Schneider, Phys. Rev. B 50, 17560 (1994).
[5] J. Li, W.-D. Schneider, R. Berndt, S. Crampin, Phys. Rev. Lett. 80, 3332 (1998)
[6] J. Li, W.-D. Schneider, R. Berndt, O. R. Bryant, and S. Crampin, Phys. Rev. Lett. 81, 4464 (1998).
[7] C. Brun, I.-P. Hong, F. Patthey, I. Yu. Sklyadneva, R. Heid, P. M. Echenique, K. P. Bohnen,
E. V. Chulkov, and W.-D. Schneider, Phys. Rev. Lett. (2009), in press.
[8] I.-P. Hong, C. Brun, F. Patthey, and W.-D. Schneider, (2009), submitted.
[9] F. Silly, M. Pivetta, M. Ternes, F. Patthey, J. P. Pelz, and W.-D. Schneider, Phys. Rev. Lett. 92, 016101 (2004).
[10] M. Ternes, C. Weber, M. Pivetta, F. Patthey, J. P. Pelz, T. Giamarchi, F. Mila, and W.-D. Schneider,
Phys. Rev. Lett. 93, 146805 (2004).
[11] F. Silly , M. Pivetta, M. Ternes, F. Patthey, J. P. Pelz, and W.-D. Schneider, New J. Phys. 6, 16 (2004).
[12] N. N. Negulyaev, V. S. Stepanyuk, L. Niebergall, P. Bruno, M. Pivetta, M. Ternes,
F. Patthey, and W.-D. Schneider, (2009), submitted.
[13] M. Böhringer, K. Morgenstern, W.-D. Schneider, R. Berndt, F. Mauri, A. De Vita, R. Car,
Phys. Rev. Lett. 83, 324 (1999).
[14] M.-C. Blüm, E. Cavar, M. Pivetta, F. Patthey, W.-D. Schneider, Angew. Chem. Int. Ed. 44, 5334 (2005).
[15] M.-C. Blüm, M. Pivetta, F. Patthey, and W.-D. Schneider, Phys. Rev. B 73, 195409 (2006).
[16] M. Pivetta, M.-C. Blüm, F. Patthey, and W.-D. Schneider, Angew. Chem. Int. Ed. 47, 1076 (2008).
[17] M. Pivetta, M.-C. Blüm, F. Patthey, and W.-D. Schneider, J. Chem. Phys. B 113, 4578 (2009).
[18] M. Pivetta, M. Ternes, F. Patthey, and W.-D. Schneider, Phys. Rev. Lett. 99, 126104 (2007).
[19] R. Berndt, R. Gaisch, J.K. Gimzewski, B. Reihl, R.R. Schlittler, W.-D. Schneider,M. Tschudy, Science 262, 1425 (1993).
[20] E. Cavar, M.-C. Blüm, M. Pivetta, F. Patthey, M. Chergui, and W.-D. Schneider, Phys. Rev. Lett. 95, 196102 (2005).
[21] F. Rossel, M. Pivetta, F. Patthey, and W.-D. Schneider, Optics Express 17, 2714 (2009). |
| A.K. Shulka (Institut Jean Lamour - Nancy) |
|---|
| Quantum size effects in the thin metal films grown on quasicrystalline surfaces |
| We have studied the growth and electronic structure of Ag films on 5-fold surface of icosahedral (i)-Al-Cu-Fe quasicrystal using scanning tunneling microscopy (STM), ultra-violet photoemission spectroscopy (UPS) and low energy electron diffraction (LEED). Magic height islands of Ag are observed by STM and these are related to the quantum size effects (QSE). LEED pattern shows that Ag grows in 5-fold twinned nanocrystallites with Ag(111) structure for > 7 monolayers and Ag(111) structure is well supported by the UPS spectra of bulk-like thick Ag films. Observations of Ag sp quantum well states (QWS) in the UPS spectra of Ag/i-Al-Cu-Fe confirmed the QSE. Mismatch in the symmetry of electronic states has been attributed to the origin of the QWS. |
| Antonio Tejeda (Nancy Université / synchrotron S) |
|---|
| Tailoring electronic and magnetic properties in structured Au surfaces |
| Tailoring electronic and magnetic properties at the nanoscale presents both technological and fundamental interest. Magnetic interactions among nanostructures and confinement conditions for electronic states can be studied in surface systems. Ideal playgrounds to study these aspects are vicinal and faceted surfaces of noble metal surfaces. In these systems, it is possible to induce magnetic stripes and high density magnetic islands lattices by self-organisation. We will show how the lattices influence the nearly-free Shockley state at the (111) face of noble metals via the modifications of the surface potential. The superposition of the potential of steps and that of magnetic islands leads to a two dimensional lattice of interacting quantum boxes for the surface state. |
|
