Publications by Klaus Kern | EPFL Graph Search

Visualizing hot carrier dynamics by nonlinear optical spectroscopy at the atomic length scale

Probing and manipulating the spatiotemporal dynamics of hot carriers in nanoscale metals is crucial to a plethora of applications ranging from nonlinear nanophotonics to single-molecule photochemistry. The direct investigation of these highly non-equilibri ...

Springer Science and Business Media LLC2025

Charge Transfer of Metal Porphyrins on a NaCl Thin Film Observed by Scanning Tunneling Microscopy in the Transport Gap

Klaus Kern

Elucidating the electronic structure of organic molecules in contact with a dielectric layer is essential to understanding and controlling many important processes, such as catalysis, photochemistry, and electroluminescence. However, this challenge calls f ...

American Chemical Society (ACS)2025

Single-Molecule Phosphorescence and Intersystem Crossing in a Coupled Exciton Plasmon System

Klaus Kern

American Chemical Society (ACS)2025

Nanoscale Mapping of Magnetic Auto-Oscillations with a Single Spin Sensor

Klaus Kern

Spin Hall nano-oscillators convert DC to magnetic auto-oscillations in the microwave regime. Current research on these devices is dedicated to creating next-generation energy-efficient hardware for communication technologies. Despite intensive research on ...

2025

Attosecond microscopy -Advances and outlook

Klaus Kern

Attosecond microscopy aims to record electron movement on its natural length and time scale. It is a gateway to understanding the interaction of matter and light, the coupling between excitations in solids, and the resulting energy flow and decoherence b ...

IOP Publishing - EPL Association2025

Investigation of Interface Interactions Between Monolayer MoS2 and Metals: Implications on Strain and Surface Roughness

Klaus Kern

Achieving a low contact resistance has been an important issue in the design of two-dimensional (2D) semiconductor-metal interfaces. The metal contact resistance is dominated by interfacial interactions. Here, we systematically investigate 2D semiconductor ...

2024

Controlled Formation of Nanoribbons and Their Heterostructures via Assembly of Mass-Selected Inorganic Ions

Klaus Kern

Control of nanomaterial dimensions with atomic precision through synthetic methods is essential to understanding and engineering of nanomaterials. For single-layer inorganic materials, size and shape controls have been achieved by self-assembly and surface ...

Wiley-V C H Verlag Gmbh2024

Scanning Tunneling Microscopy for Molecules: Effects of Electron Propagation into Vacuum

Klaus Kern, Abhishek Grewal

Using scanning tunneling microscopy (STM), we experimentally and theoretically investigate isolated platinum phthalocyanine (PtPc) molecules adsorbed on an atomically thin NaCl(100) film vapor deposited on Au(111). We obtain good agreement between theory a ...

Amer Chemical Soc2024

Tracking a spin-polarized superconducting bound state across a quantum phase transition

Klaus Kern

The magnetic exchange coupling between magnetic impurities and a superconductor induce so-called Yu-Shiba-Rusinov (YSR) states which undergo a quantum phase transition (QPT) upon increasing the exchange interaction beyond a critical value. While the evolut ...

Nature Portfolio2024

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

Real-time tracking of coherent oscillations of electrons in a nanodevice by photo-assisted tunnelling

Klaus Kern

Coherent collective oscillations of electrons excited in metallic nanostructures (localized surface plasmons) can confine incident light to atomic scales and enable strong light-matter interactions, which depend nonlinearly on the local field. Direct sampl ...

NATURE PORTFOLIO2024

Imaging conformations of holo- and apo-transferrin on the single-molecule level by low-energy electron holography

Klaus Kern

Conformational changes play a key role in the biological function of many proteins, thereby sustaining a multitude of processes essential to life. Thus, the imaging of the conformational space of proteins exhibiting such conformational changes is of great ...

Nature Portfolio2023

Charging and Electric Field Effects on Hydrogen Molecules Physisorbed on Graphene

Klaus Kern, Shai Mangel, Alessio Scavuzzo, Tobias Wollandt

Molecular hydrogen adsorbed on graphene was investigated by analyzing rotational excitation spectra obtained with a gate-tunable scanning tunneling microscope (STM). Through the shift of the rotational excitation energy, the tunability of physisorbed H2 on ...

AMER CHEMICAL SOC2023

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

Direct observation of glycans bonded to proteins and lipids at the single-molecule level

Klaus Kern, Stephan Rauschenbach

Proteins and lipids decorated with glycans are found throughout biological entities, playing roles in biological functions and dysfunctions. Current analytical strategies for these glycan-decorated biomolecules, termed glycoconjugates, rely on ensemble-ave ...

American Association for the Advancement of Science2023

Character of Electronic States in the Transport Gap of Molecules on Surfaces

Klaus Kern, Abhishek Grewal

We report on scanningtunneling microscopy (STM) topographs ofindividual metal phthalocyanines (MPc) on a thin salt (NaCl) filmadsorbed on a gold substrate, at tunneling energies within the molecule'selectronic transport gap. Theoretical models of increasin ...

AMER CHEMICAL SOC2023

Molecular sensitised probe for amino acid recognition within peptide sequences

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

Visualizing Chiral Interactions in Carbohydrates Adsorbed on Au(111) by High-Resolution STM Imaging

Klaus Kern, Stephan Rauschenbach, Uta Schlickum

Carbohydrates are the most abundant organic material on Earth and the structural "material of choice" in many living systems. Nevertheless, design and engineering of synthetic carbohydrate materials presently lag behind that for protein and nucleic acids. ...

Wiley-VCH Verlag GmbH2023

Seeding and Emergence of Composite Skyrmions in a van der Waals Magnet

Klaus Kern, Marko Burghard, Lukas Powalla

Topological charge plays a significant role in a range of physical systems. In particular, observations of real-space topological objects in magnetic materials have been largely limited to skyrmions - states with a unitary topological charge. Recently, mor ...

Wiley-V C H Verlag Gmbh2023

Universal scaling of tunable Yu-Shiba-Rusinov states across the quantum phase transition

Klaus Kern, Haonan Huang

Quantum magnetic impurities give rise to a wealth of phenomena attracting tremendous research interest in recent years. On a normal metal, magnetic impurities generate the correlation-driven Kondo effect. On a superconductor, bound states emerge inside the ...

NATURE PORTFOLIO2023