arXiv subjects

Peter Schmitz

Publications and source records attributed to Peter Schmitz.

3 recordsLinked to original sources

arXiv2025

Coexistence and tunability of orbital and spin Hall effects in RuO$_2$

Altermagnetic materials, especially RuO$_2$, have recently attracted considerable attention for their unique magnetic properties and energy-efficient spintronic applications. However, recent experimental studies have reported highly conflicting signatures regarding altermagnetic spin splitting and charge--spin interconversion (CSI) in RuO$_2$. While some experiments link efficient CSI to non-relativistic altermagnetic spin-splitting effects, others observe large CSI signals in non-spin-splitting RuO$_2$, which are instead explained by relativistic inverse spin Hall effects. In this work, based on first-principles calculations, we reveal that these controversial experimental results originate from a phase-dependent coexistence and relative dominance of the orbital Hall effect (OHE) and spin Hall effect (SHE) in RuO$_2$. We systematically investigate the OHE and SHE in both altermagnetic and nonmagnetic phases of RuO$_2$. Our results show that the altermagnetic state hosts a giant OHE that exceeds the SHE by two orders of magnitude and carries an opposite sign. This dominant OHE can generate experimentally observed "SHE-like" voltages through orbital-to-spin conversion, explaining previously reported altermagnetic CSI signals. In contrast, OHE of nonmagnetic RuO$_2$ is suppressed and a large relativistic SHE emerges, in agreement with recent angle-resolved photoemission and spin-pumping experiments. Finally, we demonstrate that the coexistence of OHE and SHE is tunable via chemical doping, enabling on-demand modulation of CSI in in RuO$_2$. Our work provides a new physical mechanism for understanding CSI in RuO$_2$ and highlights the central role of orbital transport.

cond-mat.mtrl-sci↗

arXiv2023

Promoting $p$-based Hall effects by $p$-$d$-$f$ hybridization in Gd-based dichalcogenides

We conduct a first-principles study of Hall effects in rare-earth dichalcogenides, focusing on monolayers of the H-phase EuX$_2$ and GdX$_2$, where X = S, Se, and Te. Our predictions reveal that all EuX$_2$ and GdX$_2$ systems exhibit high magnetic moments and wide bandgaps. We observe that while in case of EuX$_2$ the $p$ and $f$ states hybridize directly below the Fermi energy, the absence of $f$ and $d$ states of Gd at the Fermi energy results in $p$-like spin-polarized electronic structure of GdX$_2$, which mediates $p$-based magnetotransport. Notably, these systems display significant anomalous, spin, and orbital Hall conductivities. We find that in GdX$_2$ the strength of correlations controls the relative position of $p$, $d$ and $f$-states and their hybridization which has a crucial impact on $p$-state polarization and the anomalous Hall effect, but not the spin and orbital Hall effect. Moreover, we find that the application of strain can significantly modify the electronic structure of the monolayers, resulting in quantized charge, spin and orbital transport in GdTe$_2$ via a strain-mediated orbital inversion mechanism taking place at the Fermi energy. Our findings suggest that rare-earth dichalcogenides hold promise as a platform for topological spintronics and orbitronics.

cond-mat.mes-hall↗

arXiv2017

Linking Sketches and Diagrams to Source Code Artifacts

Recent studies have shown that sketches and diagrams play an important role in the daily work of software developers. If these visual artifacts are archived, they are often detached from the source code they document, because there is no adequate tool support to assist developers in capturing, archiving, and retrieving sketches related to certain source code artifacts. This paper presents SketchLink, a tool that aims at increasing the value of sketches and diagrams created during software development by supporting developers in these tasks. Our prototype implementation provides a web application that employs the camera of smartphones and tablets to capture analog sketches, but can also be used on desktop computers to upload, for instance, computer-generated diagrams. We also implemented a plugin for a Java IDE that embeds the links in Javadoc comments and visualizes them in situ in the source code editor as graphical icons.

cs.SE↗