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Oct 5, 2024 | 
link.springer.com | Muhammad Sufyan |Institut für Physik
AbstractTwo-dimensional materials with chemical formula MA2Z4 are a promising class of materials for optoelectronic applications. To exploit their potential, their stability with respect to air pollution has to be analyzed under different conditions. In a first-principle study based on density functional theory, we investigate the adsorption of three common environmental gas molecules (O2, H2O, and CO2) on monolayer WSi2N4, an established representative of the MA2Z4 family.
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Aug 5, 2024 | 
link.aps.org | Quancheng Liu |Advanced Materials |Klaus Ziegler |Institut für Physik
The evolution of noninteracting bosons in the presence of repeated projective measurements is studied. Following the established approach, this monitored evolution is characterized by the first detected return and the first detected transition probabilities. We show that these quantities are directly related to the entanglement entropy and the entanglement spectrum of a bipartite system.
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Jun 20, 2024 | 
onlinelibrary.wiley.com | Institut für Physik |Johannes Gutenberg-Universität Mainz |Deutsches Elektronen-Synchrotron DESY
Imaging bandpass filters play an important role in photoelectron spectroscopy. Such filters can transport either real-space images, as studied in detail by Tonner (1990), or momentum-space images, as pioneered by Krömker et al. (2008). The latter family of instruments established a new type of angle-resolved photoelectron spectroscopy (ARPES) called momentum microscopy.
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Feb 26, 2024 | 
link.aps.org | Oliver Busch |Institut für Physik |Martin Luther Halle-Wittenberg |Franziska Ziolkowski
The orbital Hall effect can generate currents of angular momentum more efficiently than the spin Hall effect in most metals. However, so far, it has only been understood as a steady-state phenomenon. In this theoretical study, the orbital Hall effect is extended into the time domain. We investigate the orbital angular momenta and their currents induced by a femtosecond laser pulse in a Cu nanoribbon.
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Nov 22, 2023 | 
pubs.aip.org | Institut für Physik |IRIS Adlershof |Humboldt-Universität zu Berlin
Organic–inorganic halide perovskites (referred to as perovskites hereafter) are a promising next-generation optoelectronic material for light-emitting diodes (LEDs), solar cells, and photodetectors because of their exceptional optoelectronic properties such as a high light absorption coefficient, tunable bandgap, outstanding carrier mobility, and long carrier diffusion length.1–9 However, their inherent structural instability and susceptibility to environmental conditions (light,10–15...
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Nov 2, 2023 | 
link.aps.org | Oliver Busch |Institut für Physik |Martin Luther Halle-Wittenberg |Franziska Ziolkowski
Laser radiation incident on a ferromagnetic sample produces excited electrons and currents whose spin polarization must not be aligned with the magnetization—an effect due to spin-orbit coupling that is ubiquitous in spin- and angle-resolved photoemission. In this paper, we report on a systematic investigation of the dynamics of spin polarization and spin-polarized currents produced by femtosecond laser pulses, modeled within our theoretical framework evolve.
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Oct 30, 2023 | 
link.aps.org | Institut für Physik |Martin-Luther-Universität Halle-Wittenberg |Ingrid Mertig
Magnetic skyrmions are nano-sized topologically nontrivial spin textures that can be moved by external stimuli such as spin currents and internal stimuli such as spatial gradients of a material parameter. Since the total energy of a skyrmion depends linearly on most of these parameters, like the perpendicular magnetic anisotropy, the exchange constant, or the Dzyaloshinskii-Moriya interaction strength, a skyrmion will move uniformly in a weak parameter gradient.
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Oct 17, 2023 | 
link.aps.org | Oliver Busch |Institut für Physik |Martin-Luther-Universität Halle-Wittenberg |Ingrid Mertig
An orbital current can be generated whenever an object has a translational degree of freedom and a rotational degree of freedom. In condensed matter physics, intra-atomic contributions to the transverse orbital transport, labeled the orbital Hall effect, rely on propagating wave packets that must consist of hybridized atomic orbitals. However, interatomic contributions have to be considered as well because they give rise to an alternative mechanism for generating orbital currents.
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Oct 3, 2023 | 
link.aps.org | Institut für Physik |Laboratoire Charles Coulomb |Pablo Rodriguez-Lopez |Svend-Age Biehs
We study the heat transfer between N coupled quantum resonators with applied synthetic electric and magnetic fields realized by changing the resonator parameters by external drivings. To this end we develop two general methods, based on the quantum optical master equation and on the Langevin equation for N coupled oscillators where all quantum oscillators can have their own heat baths.
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Sep 8, 2023 | 
link.aps.org | Oliver Busch |Institut für Physik |Martin Luther Halle-Wittenberg |Franziska Ziolkowski
The orbital angular momenta (OAM) of electrons play an increasingly important role in ultrafast electron and magnetization dynamics. In this theoretical study, we investigate the electron dynamics induced by femtosecond laser pulses in a normal metal, a ferromagnet, and a ferromagnet/normal metal heterostructure. We analyze the spatiotemporal distributions of the laser-induced OAM and their respective currents.
