arXiv subjects

Marco Weiss

Publications and source records attributed to Marco Weiss.

4 recordsLinked to original sources

arXiv2025

Measurement and Qualitative Explanation of Decay Lengths of Attractive and Repulsive Forces between Natural and Artificial Atoms

Artificial atoms, such as quantum corrals, offer an excellent platform to study fundamental interactions between localized quantum states and nanoscale probes. We performed atomic force microscopy measurements inside square quantum corrals on Cu(111) using CO- and metal-terminated tips. Using chemically unreactive CO-terminated tips repulsive Pauli forces can be probed, while metallic tips are attracted to the localized quantum states due to chemical bonding. We found distinct exponential decay constants of 46 pm for the repulsive and 66 pm for the attractive forces. Attractive and repulsive interactions between two natural atoms show significantly shorter decay lengths. While natural atoms feature states with a broad range of decay lengths, including very short ones from deeply bound states, quantum corrals are lacking such deeply bound and highly localized states, resulting in longer decay lengths. These results offer a new route to understand and design atomic-scale interactions in low-dimensional quantum structures and devices.

cond-mat.mes-hall↗

arXiv2023

Toward a Mapping of Capability and Skill Models using Asset Administration Shells and Ontologies

In order to react efficiently to changes in production, resources and their functions must be integrated into plants in accordance with the plug and produce principle. In this context, research on so-called capabilities and skills has shown promise. However, there are currently two incompatible approaches to modeling capabilities and skills. On the one hand, formal descriptions using ontologies have been developed. On the other hand, there are efforts to standardize submodels of the Asset Administration Shell (AAS) for this purpose. In this paper, we present ongoing research to connect these two incompatible modeling approaches. Both models are analyzed to identify comparable as well as dissimilar model elements. Subsequently, we present a concept for a bidirectional mapping between AAS submodels and a capability and skill ontology. For this purpose, two unidirectional, declarative mappings are applied that implement transformations from one modeling approach to the other - and vice versa.

cs.SE↗

arXiv2023

Unexpected Gaussian line shapes reveal electron-adsorbate interaction as dominant broadening mechanism in quantum corrals

Understanding the factors influencing the lifetime of electronic states in artificial quantum structures is of great significance for advancing quantum technologies. This study focuses on CO-based quantum corrals on Cu(111). Tunneling spectroscopy measurements reveal a strong correlation between the size of the quantum corral and spectral width, characterized by a predominant Gaussian line shape. We attribute this dominant Gaussian-shaped lifetime broadening to the interaction of surface state electrons with the corral boundary. To further investigate this phenomenon, we constructed corrals of varying wall densities. Our findings indicate that elastic processes, such as tunneling, are more sensitive to wall density than coupling to the bulk.

cond-mat.mes-hall↗

arXiv2023

On the origin and elimination of cross coupling between tunneling current and excitation in scanning probe experiments that utilize the qPlus sensor

The qPlus sensor allows simultaneous measurements of scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Its design for use in frequency modulation AFM (FM-AFM) involves separate electrodes, applied on an oscillating quartz cantilever, for the detection of an electronic tunneling current and the deflection signal. Cable resistance and capacities in the electronic setup can induce cross talk phenomena. We report a tunneling current-induced cross coupling observed in a combined STM/AFM setup which uses the qPlus sensor. This cross coupling can induce a positive or negative change of the amplitude excitation signal, thus acting as an apparent dissipation or drive. The experimental data is explained well by tunneling current-induced fluctuations of the electric potential on the sensor electrodes.

cond-mat.mes-hall↗