A5002067585- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Iron-based superconductors research
- Magnetic and transport properties of perovskites and related materials
- Theoretical and Computational Physics
- Quantum many-body systems
- Advanced Chemical Physics Studies
- Gas Dynamics and Kinetic Theory
- Advanced Mathematical Modeling in Engineering
- Magnetic properties of thin films
- Semiconductor materials and devices
- Quantum, superfluid, helium dynamics
- Surface and Thin Film Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
University of Würzburg
2018-2024
Technische Universität Ilmenau
2020
Brown University
2014
The coupling of a spin to an underlying substrate is the basis for plethora phenomena. In case metallic substrate, Kondo screening adatom magnetic moment can occur. As turns superconducting, intriguing situation emerges where pair breaking due spins leads Yu-Shiba-Rusinov bound states, but also intertwines with Through scanning tunneling spectroscopy, we analyze interdependence and superconductivity. Our data obtained on single Fe adatoms Nb(110) show that resulting YSR states are strongly...
We demonstrate that a finite-doping quantum critical point (QCP) naturally descends from the existence of first-order Mott transition in phase diagram strongly correlated material. In prototypical case surface associated with equation state for homogeneous system is "folded" so range parameters stable metallic and insulating phases exist are connected by an unstable branch. Here we show tuning chemical potential, zero-temperature gradually unfolds. Under general conditions, find evolves into...
We derive equations of motion for Green's functions the multiorbital Anderson impurity model by differentiating symmetrically with respect to all time arguments. The resulting relate one- and two-particle function correlators up six particles at four times. As an application we consider continuous-time quantum Monte Carlo simulations in hybridization expansion, which hitherto suffered from notoriously high noise levels large Matsubara frequencies. Employing derived symmetric improved...
Due to the intrinsic complexity of quantum many-body problem, Monte Carlo algorithms and their corresponding configurations can be defined in various ways. Configurations few Feynman diagrams often lead severe sign problems. On other hand, computing configuration weight becomes numerically expensive opposite limit which many are grouped together. Here we show that for continuous-time hybridization expansion efficiency substantially improved by dividing local impurity trace into fragments,...
We show how the stability conditions for a system of interacting fermions that conventionally involve variations thermodynamic potentials can be rewritten in terms one- and two-particle correlators. illustrate applicability this alternative formulation multiorbital model strongly correlated electrons at finite temperatures, inspecting lowest eigenvalues generalized local charge susceptibility proximity phase-separation region. Additionally to conventional unstable branches, we address...
Using a numerically exact first-principles many-body approach, we revisit the "prototypical" Kondo case of cobalt impurity on copper. Even though this is considered well understood example effect, reveal an unexpectedly strong dependence screening properties parametrization local Coulomb tensor. As consequence, temperature can vary by orders magnitude depending complexity electron-electron interaction. Further, challenge established picture spin-1 moment involving two d orbitals only, as...
We describe a simple method to determine, from ab initio calculations, the complete orientation-dependence of interfacial free energies in solid-state crystalline systems. illustrate with an application precipitates Al-Ti alloy system. The combines cluster expansion formalism its most general form (to model system's energetics) inversion well-known Wulff construction recover equilibrium precipitate shapes). Although inverse only provides relative magnitude various energies, absolute can be...
We show how the stability conditions for a system of interacting fermions that conventionally involve variations thermodynamic potentials can be rewritten in terms local one- and two-particle correlators. illustrate applicability this alternative formulation multi-orbital model strongly correlated electrons at finite temperatures, inspecting lowest eigenvalues generalized charge susceptibility proximity phase-separation region. Additionally to conventional unstable branches, we address...
This paper combines experimental and theoretical work on linear atomic chains containing a single Kondo impurity nonmagnetic metal atoms, to show the suppression of effect in specific clusters
Strongly correlated materials often undergo a Mott metal-insulator transition, which is tipically first-order, as function of control parameters like pressure. Upon doping, rich phase diagrams with competing instabilities are found. Yet, the conceptual link between interaction-driven transition and finite-doping behavior lacks clear connection theory critical phenomena. In prototypical case first-order surface associated equation state for homogeneous system "folded" so that in range stable...