References of "PHYSICAL REVIEW B"
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See detailBenzene adsorbed on metals: Concerted effect of covalency and van der Waals bonding
Liu, Wei; Carrasco, Javier; Santra, Biswajit et al

in PHYSICAL REVIEW B (2012), 86(24),

The adsorption of aromatic molecules on metal surfaces plays a key role in condensed matter physics and functional materials. Depending on the strength of the interaction between the molecule and the ... [more ▼]

The adsorption of aromatic molecules on metal surfaces plays a key role in condensed matter physics and functional materials. Depending on the strength of the interaction between the molecule and the surface, the binding is typically classified as either physisorption or chemisorption. Van der Waals (vdW) interactions contribute significantly to the binding in physisorbed systems, but the role of the vdW energy in chemisorbed systems remains unclear. Here we study the interaction of benzene with the (111) surface of transition metals, ranging from weak adsorption (Ag and Au) to strong adsorption (Pt, Pd, Ir, and Rh). When vdW interactions are accurately accounted for, the barrier to adsorption predicted by standard density-functional theory (DFT) calculations essentially vanishes, producing a metastable precursor state on Pt and Ir surfaces. Notably, vdW forces contribute more to the binding of covalently bonded benzene than they do when benzene is physisorbed. Comparison to experimental data demonstrates that some of the recently developed methods for including vdW interactions in DFT allow quantitative treatment of both weakly and strongly adsorbed aromatic molecules on metal surfaces, extending the already excellent performance found for molecules in the gas phase. [less ▲]

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See detailFluctuation theorems for capacitively coupled electronic currents
Cuetara, Gregory Bulnes; Esposito, Massimiliano UL; Gaspard, Pierre

in Physical Review B (2011), 84(16),

The counting statistics of electron transport is studied theoretically in a system with two capacitively coupled parallel transport channels. Each channel is composed of a quantum dot connected by ... [more ▼]

The counting statistics of electron transport is studied theoretically in a system with two capacitively coupled parallel transport channels. Each channel is composed of a quantum dot connected by tunneling to two reservoirs. The nonequilibrium steady state of the system is controlled by two affinities or thermodynamic forces, each one determined by the two reservoirs of each channel. The status of a single-current fluctuation theorem is investigated starting from the fundamental two-current fluctuation theorem, which is a consequence of microreversibility.We show that the single-current fluctuation theorem holds in the limit of a large Coulomb repulsion between the two parallel quantum dots, as well as in the limit of a large current ratio between the parallel channels. In this latter limit, the symmetry relation of the single-current fluctuation theorem is satisfied with respect to an effective affinity that is much lower than the affinity determined by the reservoirs. This backaction effect is characterized quantitatively. [less ▲]

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See detailSputtering at grazing ion incidence: Influence of adatom islands
Rosandi, Yudi; Redinger, Alex UL; Michely, Thomas et al

in PHYSICAL REVIEW B (2010), 82(12),

When energetic ions impinge at grazing incidence onto an atomically flat terrace, they will not sputter. However, when adatom islands (containing N atoms) are deposited on the surface, they induce ... [more ▼]

When energetic ions impinge at grazing incidence onto an atomically flat terrace, they will not sputter. However, when adatom islands (containing N atoms) are deposited on the surface, they induce sputtering. We investigate this effect for the specific case of 83 degrees-incident 5 keV Ar ions on a Pt (111) surface by means of molecular-dynamics simulation and experiment. We find that-for constant coverage Theta-the sputter yield has a maximum at island sizes of N congruent to 10-20. A detailed picture explaining the decline of the sputter yield toward larger and smaller island sizes is worked out. Our simulation results are compared with dedicated sputtering experiments, in which a coverage 0.09 of Pt adatoms are deposited onto the Pt (111) surface and form islands with a broad distribution around a most probable size of N congruent to 20. [less ▲]

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See detailMolecular structure of the H2O wetting layer on Pt(111)
Standop, Sebastian; Redinger, Alex UL; Morgenstern, Markus et al

in PHYSICAL REVIEW B (2010), 82(16),

The molecular structure of the wetting layer of ice on Pt(111) is resolved using scanning tunneling microscopy. Two structures observed previously by diffraction techniques are imaged for coverages at or ... [more ▼]

The molecular structure of the wetting layer of ice on Pt(111) is resolved using scanning tunneling microscopy. Two structures observed previously by diffraction techniques are imaged for coverages at or close to completion of the wetting layer. At 140 K only a root 37 x root 37R25.3 degrees superstructure can be established while at 130 K also a root 39 x root 39R16.1 degrees superstructure with slightly higher molecular density is formed. In the temperature range under concern the superstructures reversibly transform into each other by slight changes in coverage through adsorption or desorption. The superstructures exhibit a complex pattern of molecules in different geometries. [less ▲]

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See detailReaching optimal efficiencies using nanosized photoelectric devices
Rutten, B.; Esposito, Massimiliano UL; Cleuren, B.

in Physical Review B (2009), 80(23),

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See detailNear Kohn anomalies in the phonon dispersion relations of lead chalcogenides
Kilian, Ondrej; Allan, Guy; Wirtz, Ludger UL

in Physical Review B (2009), 80(24),

We present ab initio phonon dispersion relations for the three lead chalcogenides PbS, PbSe, and PbTe. The acoustic branches are in very good agreement with inelastic neutron-scattering data and ... [more ▼]

We present ab initio phonon dispersion relations for the three lead chalcogenides PbS, PbSe, and PbTe. The acoustic branches are in very good agreement with inelastic neutron-scattering data and calculations of the specific heat give good agreement with experimental data. The pronounced minimum of the transverse-optical branch at Gamma due to the near ferroelectricity of the lead chalcogenides is qualitatively reproduced. In addition, we find a pronounced dip in the longitudinal-optical branch at Gamma. This dip was previously explained as the effect of "free carriers" (due to the presence of impurities). The calculations demonstrate that it persists also in the case of pure lead chalcogenides. We explain the dip as a "near Kohn anomaly" which is associated with the small electronic band gap at the high-symmetry point L. [less ▲]

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See detailPhonon surface mapping of graphite: Disentangling quasi-degenerate phonon dispersions
Grueneis, A.; Serrano, J.; Bosak, A. et al

in Physical Review B (2009), 80(8),

The two-dimensional mapping of the phonon dispersions around the K point of graphite by inelastic x-ray scattering is provided. The present work resolves the longstanding issue related to the correct ... [more ▼]

The two-dimensional mapping of the phonon dispersions around the K point of graphite by inelastic x-ray scattering is provided. The present work resolves the longstanding issue related to the correct assignment of transverse and longitudinal phonon branches at K. We observe an almost degeneracy of the three TO-, LA-, and LO-derived phonon branches and a strong phonon trigonal warping. Correlation effects renormalize the Kohn anomaly of the TO mode, which exhibits a trigonal warping effect opposite to that of the electronic band structure. We determined the electron-phonon coupling constant to be 166 (eV/A degrees)(2) in excellent agreement to GW calculations. These results are fundamental for understanding angle-resolved photoemission, double-resonance Raman and transport measurements of graphene-based systems. [less ▲]

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See detailVanishing gap in LiF for electronic excitations by slow antiprotons
Solleder, Beate; Wirtz, Ludger UL; Burgdörfer, Joachim

in Physical Review B (2009), 79(12),

We study the influence of antiprotons and protons traveling through LiF on the band structure of the insulator using the embedded-cluster method. The crystal is represented by F(m)(-)Li(n)(+) clusters ... [more ▼]

We study the influence of antiprotons and protons traveling through LiF on the band structure of the insulator using the embedded-cluster method. The crystal is represented by F(m)(-)Li(n)(+) clusters with up to 19 fluorine ions embedded in a lattice of point charges representing the remainder of the crystal. The minimum excitation energy of LiF perturbed by the (anti)proton impurity is calculated employing the multiconfiguration self-consistent field method. The repulsive potential of the antiproton causes a dramatic local perturbation of the LiF band structure. We find a strong suppression of the excitation energy by more than an order of magnitude compared to that of the unperturbed crystal. The present results provide a simple explanation of recent stopping-power experiments for antiprotons in LiF which, surprisingly, found a "metal-like" behavior of the wide-band-gap insulator LiF. Our results also agree with recent experimental data indicating a deviation from metallic behavior of the stopping power of proton projectiles. [less ▲]

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See detailTransport in molecular states language: Generalized quantum master equation approach
Esposito, Massimiliano UL; Galperin, Michael

in Physical Review B (2009), 79(20),

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See detailUltrafast electron-phonon decoupling in graphite
Ishioka, Kunie; Hase, Muneaki; Kitajima, Masahiro et al

in Physical Review B (2008), 77(12),

We report the ultrafast dynamics of the 47.4 THz coherent phonons of graphite interacting with a photoinduced nonequilibrium electron-hole plasma. Unlike conventional materials, upon photoexcitation the ... [more ▼]

We report the ultrafast dynamics of the 47.4 THz coherent phonons of graphite interacting with a photoinduced nonequilibrium electron-hole plasma. Unlike conventional materials, upon photoexcitation the phonon frequency of graphite upshifts, and within a few picoseconds relaxes to the stationary value. Our first-principles density functional calculations demonstrate that the phonon stiffening stems from the light-induced decoupling of the nonadiabatic electron-phonon interaction by creating a nonequilibrium electron-hole plasma. Time-resolved vibrational spectroscopy provides a window on the ultrafast nonquilibrium electron dynamics. [less ▲]

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See detailDiffractive paths for weak localization in quantum billiards
Brezinova, Iva; Stampfer, Christoph; Wirtz, Ludger UL et al

in Physical Review B (2008), 77(16),

We study the weak-localization effect in quantum transport through a clean ballistic cavity with regular classical dynamics. We address the question which paths account for the suppression of conductance ... [more ▼]

We study the weak-localization effect in quantum transport through a clean ballistic cavity with regular classical dynamics. We address the question which paths account for the suppression of conductance through a system where disorder and chaos are absent. By exploiting both quantum and semiclassical methods, we unambiguously identify paths that are diffractively backscattered into the cavity (when approaching the lead mouths from the cavity interior) to play a key role. Diffractive scattering couples transmitted and reflected paths and is thus essential to reproduce the weak-localization peak in reflection and the corresponding antipeak in transmission. A comparison of semiclassical calculations featuring these diffractive paths yields good agreement with full quantum calculations and experimental data. Our theory provides system-specific predictions for the quantum regime of few open lead modes and can be expected to be relevant also for mixed as well as chaotic systems. [less ▲]

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See detailExcitation energy and pair correlation function of trions near an LiF surface
Solleder, Beate; Wirtz, Ludger UL; Burgdörfer, Joachim

in Physical Review B (2008), 78(15),

We investigate the excitation spectrum of a singly charged LiF surface using an embedded cluster approach. The spectrum is determined by multiconfiguration self-consistent field calculations. We find ... [more ▼]

We investigate the excitation spectrum of a singly charged LiF surface using an embedded cluster approach. The spectrum is determined by multiconfiguration self-consistent field calculations. We find stable trionic states, i.e., quasimolecular states of a three-quasiparticle complex consisting of two holes and one electron interacting through the Coulomb potential. The excitation energy of the lowest trionic state is approximately 12.1 eV. The mean hole-hole spacing is about 7.6 a.u. (or 4 A). Our results confirm the interpretation of experiments [P. Roncin , Phys. Rev. Lett. 89, 043201 (2002)] where trion excitation was suggested as effective energy-loss channel during the neutralization of Ne(+) ions at an LiF surface. [less ▲]

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See detailTight-binding description of the quasiparticle dispersion of graphite and few-layer graphene
Grueneis, A.; Attaccalite, C.; Wirtz, Ludger UL et al

in Physical Review B (2008), 78(20),

A universal set of third-nearest-neighbor tight-binding (TB) parameters is presented for calculation of the quasiparticle (QP) dispersion of N stacked sp(2) graphene layers (N=1...infinity) with AB ... [more ▼]

A universal set of third-nearest-neighbor tight-binding (TB) parameters is presented for calculation of the quasiparticle (QP) dispersion of N stacked sp(2) graphene layers (N=1...infinity) with AB stacking sequence. The present TB parameters are fit to ab initio calculations on the GW level and are universal, allowing to describe the whole pi "experimental" band structure with one set of parameters. This is important for describing both low-energy electronic transport and high-energy optical properties of graphene layers. The QP bands are strongly renormalized by electron-electron interactions, which results in a 20% increase in the nearest-neighbor in-plane and out-of-plane TB parameters when compared to band structure from density-functional theory. With the new set of TB parameters we determine the Fermi surface and evaluate exciton energies, charge carrier plasmon frequencies, and the conductivities which are relevant for recent angle-resolved photoemission, optical, electron energy loss, and transport measurements. A comparision of these quantitities to experiments yields an excellent agreement. Furthermore we discuss the transition from few-layer graphene to graphite and a semimetal to metal transition in a TB framework. [less ▲]

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See detailStep-edge sputtering through grazing incidence ions investigated by scanning tunneling microscopy and molecular dynamics simulations
Redinger, Alex UL; Rosandi, Yudi; Urbassek, Herbert M. et al

in PHYSICAL REVIEW B (2008), 77(19),

Scanning tunneling microscopy is used to quantify step-edge sputtering of Pt(111) at 550 K by grazing incidence ion bombardment with 5 keV Ar(+) ions. For bombardment conditions causing negligible erosion ... [more ▼]

Scanning tunneling microscopy is used to quantify step-edge sputtering of Pt(111) at 550 K by grazing incidence ion bombardment with 5 keV Ar(+) ions. For bombardment conditions causing negligible erosion on terraces, damage features associated with step bombardment allow us to visualize step retraction and thus to quantify the step-edge sputtering yield. An alternative method for step-edge yield determination, which is applicable under more general conditions, is the analysis of the concentration of ascending steps together with the removed amount as a function of ion fluence. Interestingly, the azimuthal direction of the impinging ions with respect to the surface significantly changes the sputtering yield at step edges. This change is attributed to the orientation dependence of subsurface channeling. Atomistic insight into step-edge sputtering and its azimuthal dependence is given by molecular dynamics simulations of ion impacts at 0 and 550 K. The simulations also demonstrate a strong dependence of the step-edge sputtering yield on temperature. [less ▲]

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See detailInterference effects in the counting statistics of electron transfers through a double quantum dot
Welack, Sven; Esposito, Massimiliano UL; Harbola, Upendra et al

in Physical Review B (2008), 77(19),

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See detailImpact of the electron-electron correlation on phonon dispersion: Failure of LDA and GGA DFT functionals in graphene and graphite
Lazzeri, Michele; Attaccalite, Claudio; Wirtz, Ludger UL et al

in Physical Review B (2008), 78(8),

We compute the electron-phonon coupling (EPC) of selected phonon modes in graphene and graphite using various ab initio methods. The inclusion of nonlocal exchange-correlation effects within the GW ... [more ▼]

We compute the electron-phonon coupling (EPC) of selected phonon modes in graphene and graphite using various ab initio methods. The inclusion of nonlocal exchange-correlation effects within the GW approach strongly renormalizes the square EPC of the A(1)' K mode by almost 80% with respect to density-functional theory in the LDA and GGA approximations. Within GW, the phonon slope of the A(1)' K mode is almost two times larger than in GGA and LDA, in agreement with phonon dispersions from inelastic x-ray scattering and Raman spectroscopy. The hybrid B3LYP functional overestimates the EPC at K by about 30%. Within the Hartree-Fock approximation, the graphene structure displays an instability under a distortion following the A(1)' 'phonon at K. [less ▲]

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See detailStatistics and fluctuation theorem for boson and fermion transport through mesoscopic junctions
Harbola, Upendra; Esposito, Massimiliano UL; Mukamel, Shaul

in Physical Review B (2007), 76(8),

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See detailFluctuation theorem for counting statistics in electron transport through quantum junctions
Esposito, Massimiliano UL; Harbola, Upendra; Mukamel, Shaul

in Physical Review B (2007), 75(15),

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See detailQuantum master equation for electron transport through quantum dots and single molecules
Harbola, Upendra; Esposito, Massimiliano UL; Mukamel, Shaul

in Physical Review B (2006), 74(23),

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See detailAnalytic theory of hexagonal monolayer interacting with hexagonal substrate
Tkatchenko, Alexandre UL

in PHYSICAL REVIEW B (2006), 74(3),

Analytic theory of the infinite rigid hexagonal monolayer interacting with hexagonal substrate is developed. The interaction potential is described by a Fourier series with up to six shells of the ... [more ▼]

Analytic theory of the infinite rigid hexagonal monolayer interacting with hexagonal substrate is developed. The interaction potential is described by a Fourier series with up to six shells of the reciprocal cell vectors. It is rigorously shown that energy of minimum structures is directly related to their symmetry, assuming a decaying behavior of Fourier coefficients. Preliminary comparison with real systems of halogens and alkalis adsorbed on metal surfaces is encouraging and indicates that the adsorbate-substrate interaction is one of the main driving forces in the monolayer formation. The need of detailed ab initio calculations to obtain the Fourier coefficients for different complex adsorption systems is emphasized. Our results indicate the importance of accurate description of the adsorbate-substrate interactions for quantitative theory of monolayer epitaxy on well-ordered surfaces. [less ▲]

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