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Klaus Kern

Cette personne a quitté l’EPFL

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Publications associées (289)

Page 3 sur 15

A hydrodynamically optimized nano-electrospray ionization source and vacuum interface

Klaus Kern, Mark Pauly, Stephan Rauschenbach, Gordon Rinke

The coupling of atmospheric pressure ionization (API) sources like electrospray ionization (ESI) to vacuum based applications like mass spectrometry (MS) or ion beam deposition (IBD) is done by differential pumping, starting with a capillary or pinhole inl ...

Royal Soc Chemistry2014

Charge-transfer-induced structural rearrangements at both sides of organic/metal interfaces

Klaus Kern, Yang Wang

Organic/metal interfaces control the performance of many optoelectronic organic devices, including organic light-emitting diodes or field-effect transistors. Using scanning tunnelling microscopy, low-energy electron diffraction, X-ray photoemission spectro ...

2010

Highly Adaptable Two-Dimensional Metal-Organic Coordination Networks on Metal Surfaces

Klaus Kern, Sebastian Stepanow, Christopher Seiji Kley

The formation of extended two-dimensional metal organic coordination networks (2D-MOCNs) showing high adaptability to surface step edges and structural defects is revealed by scanning tunneling microscopy. Rod-like 4,4'-di-(1,4-buta-1,3-diynyl)-benzoic aci ...

2012

Orbital selective overlayer-substrate hybridization in a Pb monolayer on Ag(111)

Klaus Kern, Frédéric Mila, Harald Brune, Marco Grioni, Thomas Gloor, Stephan Fedrigo

The electronic structure of a Pb overlayer on Ag(111) has been studied by angle-resolved photoemission spectroscopy. We identify three p bands. While the p(xy) bands are sharp and closely resemble the corresponding bands of a free-standing Pb layer, the p( ...

2006

Chemical Modification of Graphene via Hyperthermal Molecular Reaction

Klaus Kern, Marko Burghard, Stephan Rauschenbach, Sabine Abb, Gordon Rinke

Chemical functionalization of graphene is achieved by hyperthermal reaction with azopyridine molecular ions. The one-step, room temperature process takes place in high vacuum (10(7) mbar) using an electrospray ion beam deposition (ES-IBD) setup. For ion su ...

Amer Chemical Soc2014

Controlling Single Molecule Conductance by a Locally Induced Chemical Reaction on Individual Thiophene Units

Klaus Kern, Uta Schlickum, Ivan Pentegov, Verena Katharina Schendel

Among the prerequisites for the progress of single-molecule-based electronic devices are a better understanding of the electronic properties at the individual molecular level and the development of methods to tune the charge transport through molecular jun ...

Wiley-VCH Verlag GmbH2020

Anionic character of the conduction band of sodium chloride

Klaus Kern, Abhishek Grewal

The alkali halides are ionic compounds. Each alkali atom donates an electron to a halogen atom, leading to ions with full shells. The valence band is mainly located on halogen atoms, while, in a traditional picture, the conduction band is mainly located on ...

Nature Portfolio2022

Fabry-Perot Resonances in One-Dimensional Plasmonic Nanostructures

Klaus Kern

We study the near-field optical behavior of Fabry-Perot resonances in thin metal nanowires, also referred to as quasi one-dimensional plasmonic nanoantennas. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection ...

American Chemical Society (ACS)2009

Illuminating the dark corridor in graphene: Polarization dependence of angle-resolved photoemission spectroscopy on graphene

Klaus Kern

We have used s- and p-polarized synchrotron radiation to image the electronic structure of epitaxial graphene near the (K) over bar point by angle-resolved photoemission spectroscopy (ARPES). Part of the experimental Fermi surface is suppressed due to the ...

2011

Selective excitation of vibrations in a single molecule

Klaus Kern

The capability to excite, probe, and manipulate vibrational modes is essential for understanding and controlling chemical reactions at the molecular level. Recent advancements in tip-enhanced Raman spectroscopies have enabled the probing of vibrational fin ...

Nature Portfolio2024

Modeling Ferro- and Antiferromagnetic Interactions in Metal-Organic Coordination Networks

Klaus Kern, Sebastian Stepanow, Christopher Seiji Kley

Magnetization curves of two rectangular metalorganic coordination networks formed by the organic ligand TCNQ (7,7,8,8-tetracyanoquinodimethane) and two different (Mn and Ni) 3d transition metal atoms [M(3d)] show marked differences that are explained using ...

Amer Chemical Soc2015

Molecular sensitised probe for amino acid recognition within peptide sequences

Klaus Kern, Stephan Rauschenbach, Uta Schlickum, Sabine Abb, Daniel Pablo Rosenblatt, Sebastian Koslowski

The combination of low-temperature scanning tunnelling microscopy with a mass-selective electro-spray ion-beam deposition established the investigation of large biomolecules at nanometer and sub-nanometer scale. Due to complex architecture and conformation ...

Nature Portfolio2023

Structural Analysis and Electronic Properties of Negatively Charged TCNQ: 2D Networks (TCNQ)(2)Mn Assembled on Cu(100)

Klaus Kern

A compound two-dimensional monolayer mixing Mn atoms and 7,7,8,8-tetracyanoquinoclimethane (TCNQ) molecules was synthesized by supramolecular assembly on a Cu(100) surface under ultrahigh-vacuum conditions. The interactions in the Mn(TCNQ)(2) network and i ...

2010

Ordering of dipeptide chains on Cu surfaces through 2D cocrystallization

Klaus Kern, Magalí Alejandra Lingenfelder

We report on the induced ordering of dispersed chiral diphenylalanine (Phe-Phe) chains grown on the anisotropic Cu(110) and isotropic Cu(100) surfaces. Scanning tunneling microscopy (STM) data reveal that 2D extended hybrid molecular motifs can be fabricat ...

2007

Portrait of the potential barrier at metal-organic nanocontacts

Klaus Kern

Electron transport through metal-molecule contacts greatly affects the operation and performance of electronic devices based on organic semiconductors(1-4) and is at the heart of molecular electronics exploiting single-molecule junctions(5-8). Much of our ...

2010

Quasiparticle Chirality in Epitaxial Graphene Probed at the Nanometer Scale

Klaus Kern

Graphene exhibits unconventional two-dimensional electronic properties resulting from the symmetry of its quasiparticles, which leads to the concepts of pseudospin and electronic chirality. Here, we report that scanning tunneling microscopy can be used to ...

2008

Experimental and theoretical investigations of the thermodynamic stability of Ba-C-60 and K-C-60 compound clusters

Klaus Kern

A novel experimental set-up was used to study superstable (magic) Ba-C-60 and K-C-60 compound clusters. The most stable systems observed cannot be rationalized by simple electronic or by geometrical shell filling arguments. Annealing the clusters past the ...

2008

A nanoscale gigahertz source realized with Josephson scanning tunneling microscopy

Klaus Kern, Matthias Alexander Eltschka

Using the AC Josephson effect in the superconductor-vacuum-superconductor tunnel junction of a scanning tunneling microscope (STM), we demonstrate the generation of GHz radiation. With the macroscopic STM tip acting as a lambda/4-monopole antenna, we first ...

Amer Inst Physics2015

Quantum Point Contact Microscopy

Klaus Kern

We introduce quantum point contact microscopy (QPCM) as a novel method for surface characterization, where the conductance through a quantum point contact formed by a metal atom between the tip of a scanning tunneling microscope and the surface is mapped a ...

American Chemical Society (ACS)2011

In-situ atomic level observation of the strain response of graphene lattice

Klaus Kern, Jz -Yuan Juo

Strain is inevitable in two-dimensional (2D) materials, regardless of whether the film is suspended or supported. However, the direct measurement of strain response at the atomic scale is challenging due to the difficulties of maintaining both flexibility ...

Nature Portfolio2023