Article
Chemistry, Physical
Daniel Garcia Rodriguez, Michael Gleeson, Jeppe V. Lauritsen, Zheshen Li, Xin Yu, J. W. Hans Niemantsverdriet, C. J. Kees-Jan Weststrate
Summary: Thin iron films on Cu(1 0 0) were carburized using ethylene to produce pure iron carbide surfaces. Carbon can be deposited on thin films up to a certain thickness, and it affects the structure and surface chemistry of the film.
APPLIED SURFACE SCIENCE
(2022)
Review
Physics, Multidisciplinary
Jiemin Li, Yanhong Gu, Yoshihiro Takahashi, Keisuke Higashi, Taehun Kim, Yang Cheng, Fengyuan Yang, Jan Kune, Jonathan Pelliciari, Atsushi Hariki, Valentina Bisogni
Summary: By combining resonant inelastic X-ray scattering, Anderson impurity model plus dynamical mean-field theory, and Heisenberg spin model, we investigate the spin dynamics in antiferromagnetic (AFM) α-Fe2O3 thin films. We observe a thickness-independent acoustic single-magnon mode below 100 meV and an unexpected sequence of equally spaced optical modes corresponding to multiple magnons above 100 meV. Our study reveals the energy, character, and momentum dependence of single and multimagnons in α-Fe2O3 thin films, with implications for AFM magnon transport and related phenomena.
Article
Chemistry, Physical
Jonathan Pelliciari, Sangjae Lee, Keith Gilmore, Jiemin Li, Yanhong Gu, Andi Barbour, Ignace Jarrige, Charles H. Ahn, Frederick J. Walker, Valentina Bisogni
Summary: Resonant inelastic X-ray scattering was used to investigate the spectrum of spin excitations in mesoscopic Fe films, revealing that as the thickness is reduced, ferromagnetic spin excitations in the films renormalize to lower energies along the out-of-plane direction while maintaining their dispersion in the in-plane direction. This thickness dependence was explained by Heisenberg model calculations considering the confinement in the out-of-plane direction caused by the loss of Fe bonds.
Article
Chemistry, Physical
Ming-Wei Lin, Hong-Ping Lin, Yi-Wen Ho, Ren-Han Li, Mu-Jeng Cheng, Jong-Liang Lin
Summary: Reflection-absorption infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed reaction/desorption techniques, together with density-functional-theory calculations, were used to investigate the adsorption and reaction routes of propenoyl chloride on Cu(100) and oxygen-covered Cu(100). The results showed that nucleophilic attack by adsorbed oxygen leads to the formation of propenoate and chlorine on O/Cu(100), while on Cu(100), propenoyl chloride adsorbs and undergoes breakage of the C-Cl bond to form acyl and ketene-like intermediates. The ketene-like intermediate further dimerizes to form a 3-methylene-4-ethenylidene-oxetan-2-one species.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Reihaneh Amirbeigiarab, Alexander Bagger, Jing Tian, Jan Rossmeisl, Olaf M. Magnussen
Summary: In situ scanning tunneling microscopy was used to study the (bi)carbonate adsorption on Cu(100) in 0.1 M KHCO3. Different ordered adlayer phases with (2√2 x 6 2√2)R45 degrees and (4x4) unit cells were found in the double layer potential regime. The adlayer consists of coadsorbed carbonate and water molecules and undergoes a reversible order-disorder phase transition at 0 V vs. the reversible hydrogen electrode, which is strongly stabilized by liquid water in the adjacent electrolyte.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Nanoscience & Nanotechnology
Yong-Chang Lau, Takeshi Seki, Koki Takanashi
Summary: This study presents a systematic comparative analysis of spin Hall efficiency in highly face-centered cubic (fcc) Pt-Al alloy films and poorly crystallized Pt-Al alloy films. The results indicate that fcc Pt100-xAlx alloy films grown on MgO exhibit outstanding charge-spin conversion efficiency, showing the potential for reducing power consumption compared to polycrystalline bilayers on SiO2. Improving the crystallinity of fcc Pt-based alloys is shown to be crucial for achieving large spin Hall efficiency and low power consumption.
Article
Materials Science, Multidisciplinary
Tobias Lojewski, Mohamed F. Elhanoty, Loic Le Guyader, Oscar Granaes, Naman Agarwal, Christine Boeglin, Robert Carley, Andrea Castoldi, Christian David, Carsten Deiter, Florian Doering, RobinY Engel, Florian Erdinger, Hans Fangohr, Carlo Fiorini, Peter Fischer, Natalia Gerasimova, Rafael Gort, Frank deGroot, Karsten Hansen, Steffen Hauf, David Hickin, Manuel Izquierdo, Benjamin E. Van Kuiken, Yaroslav Kvashnin, Charles-Henri Lambert, David Lomidze, Stefano Maffessanti, Laurent Mercadier, Giuseppe Mercurio, Piter S. Miedema, Katharina Ollefs, Matthias Pace, Matteo Porro, Javad Rezvani, Benedikt Roesner, Nico Rothenbach, Andrey Samartsev, Andreas Scherz, Justina Schlappa, Christian Stamm, Martin Teichmann, Patrik Thunstrom, Monica Turcato, Alexander Yaroslavtsev, Jun Zhu, Martin Beye, Heiko Wende, Uwe Bovensiepen, Olle Eriksson, Andrea Eschenlohr
Summary: By combining femtosecond time-resolved X-ray absorption spectroscopy with ab initio time-dependent density functional theory, we analyze the electronic structure of fcc Ni on a femtosecond time scale. We observe transient broadening and energy shifts in the absorption spectra, which are explained by electron repopulation and correlation-induced modifications of the electronic structure, accounting for the local Coulomb interaction.
MATERIALS RESEARCH LETTERS
(2023)
Article
Chemistry, Physical
Laura M. Jacoby, Matthew J. Crane, Daniel R. Gamelin
Summary: This research discovers the potential application of vapor-deposited CsPbBr3 thin films in optoelectronic and spin-based devices. Both photogenerated holes and electrons show coherent spin precession, but the spin dephasing time of photogenerated electrons is shorter.
CHEMISTRY OF MATERIALS
(2022)
Article
Physics, Applied
Pawel Gruszecki, Igor L. Lyubchanskii, Konstantin Y. Guslienko, Maciej Krawczyk
Summary: The excitation of high-frequency short-wavelength spin waves using the non-linear nature of magnetization dynamics was proposed in this study, demonstrating efficient excitation of plane spin waves with doubled temporal and spatial frequencies. This method shows promise for integration with an inductive or point-like spin-torque source.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Xiangnan Gong, Menglei Feng, Hong Wu, Hongpeng Zhou, Chunhung Suen, Hanjun Zou, Lijie Guo, Kai Zhou, Shijian Chen, Jiyan Dai, Guoyu Wang, Xiaoyuan Zhou
Summary: This work focuses on improving the quality of highly (100)-oriented SnSe thin films for thermoelectric applications. By controlling key parameters during pulsed-laser deposition and performing vacuum thermal annealing, the film quality was enhanced. The best crystal quality and uniform orientation were achieved on SiO2/Si substrate at 673 K followed by thermal annealing at 673 K for 30 min, showcasing promising Seebeck coefficient and power factor values.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Igor Yanilkin, Amir Gumarov, Igor Golovchanskiy, Bulat Gabbasov, Roman Yusupov, Lenar Tagirov
Summary: Experimental and theoretical studies were conducted on standing spin waves in epitaxial films of the ferromagnetic Pd1-xFex alloy with different distributions of the magnetic properties. The influence of the magnetic profile on the spin wave resonances was demonstrated, and the potential application of engineering standing spin waves in graded ferromagnetic films was discussed.
Article
Physics, Multidisciplinary
Sergey Belim, Ilya Tikhomirov
Summary: This article addresses the problem of modeling thin epitaxial iron films on a Cu (100) substrate by calculating the surface potential. The simulation aims to determine the film structure. It is found that the copper substrate stabilizes the fcc crystal lattice in the iron film at low temperatures, whereas bulk iron samples have a bcc crystal lattice. Furthermore, the interface effect causes additional vertical deformations in the first two layers of iron above the substrate.
Article
Chemistry, Physical
Jonghyuk Im, Kyungryun Lee, Sohyun Jung, Eunhee Kim, Jung Ho Lee
Summary: A newly proposed method using pre-homonuclear decoupling (PHD) applied to TROSY technique enhances the accuracy and resolution of NMR data analysis by labeling the longitudinal spin order of an a proton on multiple quantum coherences. This approach successfully achieved complete backbone resonance assignment of Tau and alpha-Syn proteins, demonstrating ultrahigh resolution in both amide proton and nitrogen dimensions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Di Yue, Weiwei Lin, C. L. Chien
Summary: Spin pumping experiments using ferromagnetic metals show efficient spin-charge conversion, possibly due to the inverse Rashba-Edelstein effect, while longitudinal spin Seebeck effect experiments using ferrimagnetic insulators do not exhibit appreciable spin-to-charge conversion. The differences between magnetic metals and magnetic insulators as spin current injectors are highlighted, with only detected voltages adhering to the inverse spin Hall effect being due to spin currents.
Article
Chemistry, Multidisciplinary
Vireshwar Mishra, Amar Kumar, Lalit Pandey, Nanhe Kumar Gupta, Soumyarup Hait, Vineet Barwal, Nikita Sharma, Nakul Kumar, Sharat Chandra, Sujeet Chaudhary
Summary: The researchers conducted various measurements on CoFeCrGa alloy thin films and performed first principles calculations, finding that the films exhibit behavior similar to spin gapless semiconductors. This material has the potential to play a significant role in spintronics-based devices.
Article
Physics, Multidisciplinary
Jing Yu, Xiaowen Chen, Fangzhou Wang, Roman Adam, Daniel E. Buergler, Lining Pan, Jing Zhang, Yuanzhi Cui, Qiuyue Li, Meihong Liu, Jie Xu, Shandong Li, Umut Parlak, Jianbo Wang, Qingfang Liu, Mirko Cinchetti, Claus M. Schneider, Derang Cao
Summary: FeCoHf films with different Hf contents and thicknesses were deposited by composition-gradient sputtering. Stripe domain structure emerged when film thickness exceeded a critical thickness, but increased Hf content led to a decrease in magnetization, weakening and eventually disappearing the stripe phase. Dynamic measurements revealed multiple resonance peaks in the absorption spectra, which can be controlled by the saturation magnetization of the film. Micromagnetic simulations attribute the multiple resonance modes to enhanced magnetization and increased magnetic domain wall volume. These findings highlight the importance of magnetic domain dynamics in spintronic and microwave devices.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Applied
Y. S. Liu, H. Xiao, C. Zhang, C. W. Zhang, Y. G. Shi, T. Hu, C. M. Schneider
Summary: We present magneto-transport measurements of WTe2 thin film devices with current applied along and perpendicular to the in-plane directions. The devices consist of a van der Waals thin film of WTe2 sandwiched between top and bottom Au electrodes. Our results reveal unsaturated magnetoresistance and Shubnikov-de Haas oscillations in the in-plane direction, as well as saturated longitudinal magnetoresistance and quantum oscillations in the out-of-plane direction in a WTe2 thin film. This study provides insights into the unsaturated magnetoresistance of WTe2 and offers potential for non-planar engineering in spintronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Iulia Cojocariu, Silvia Carlotto, Daniel Baranowski, Matteo Jugovac, Luca Schio, Luca Floreano, Maurizio Casarin, Vitaliy Feyer, Claus M. Schneider
Summary: Porphyrins show excellent adaptability in molecular nanodevices, such as gas sensing and photochemistry. The self-assembled layers of cobalt/9-octaethylporphyrins and meso-tetraphenylporphyrins on metal substrates exhibit different conformations. On the more reactive copper surface, the molecular pinning effect stabilizes the macrocycle in a planar conformation.
INORGANICA CHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Iulia Cojocariu, Andreas Windischbacher, Daniel Baranowski, Matteo Jugovac, Rodrigo Cezar de Campos Ferreira, Jiri Dolezal, Martin Svec, Jorge Manuel Zamalloa-Serrano, Massimo Tormen, Luca Schio, Luca Floreano, Jan Dreiser, Peter Puschnig, Vitaliy Feyer, Claus M. Schneider
Summary: Molecule-based functional devices can utilize surface-mediated spin state bistability. Unlike conventional spin crossover complexes, different spin states can only be accessed at temperatures below room temperature, and the high-spin state has a relatively short lifetime. However, the prototypical nickel phthalocyanine exhibits different behavior, as direct interaction with a copper metal electrode mediates the coexistence of high and low spin states within a 2D molecular array. The spin state bistability is non-volatile and originates from the surface-induced axial displacement of the functional nickel cores.
Article
Materials Science, Multidisciplinary
Bharti Parashar, Lars Rathmann, Hyun-Jung Kim, Iulia Cojocariu, Aaron Bostwick, Chris Jozwiak, Eli Rotenberg, Jose Avila, Pavel Dudin, Vitaliy Feyer, Christoph Stampfer, Bernd Beschoten, Gustav Bihlmayer, Claus M. Schneider, Lukasz Plucinski
Summary: Using microfocused angle-resolved photoemission spectroscopy, the researchers studied microstructures containing single-layer and bilayer WSe2 on graphite substrates with different twist angles. They found that electrons emitted from the graphite were diffracted when passing through the WSe2, forming band replicas observed in experimental Fermi surface maps. The researchers observed no evidence of hybridization gaps at the interlayer band-crossing points for the twisted bilayer WSe2 similar to 28 degrees and similar to 10 degrees, as well as for the single-layer WSe2 on graphite.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Peter Tutacz, Daniel Stadler, Touraj Karimpour, Tomas Duchon, Stefan Cramm, Claus Michael Schneider, Thomas Fischer, David N. Mueller, Sanjay Mathur
Summary: A new Ti(III) precursor was used in the magnetic field-assisted chemical vapor deposition process to study the external field effects on the paramagnetic metal center during film growth. The gas-phase decomposition of the precursor under variable magnetic fields showed significant shape anisotropy in the TiO2 films, which was confirmed by distinct morphological patterns and preferred crystallographic orientation of the grains. X-ray absorption spectroscopy revealed the formation of well-defined anatase-type TiO6 subunits under the field-assisted processes, while distortions towards TiO6 units of the rutile modification were observed in the zero-field experiments.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
David Moenkebuescher, Paul Rosenberger, Fabian Mertens, Roman Adam, Claus M. M. Schneider, Umut Parlak, Martina Mueller, Mirko Cinchetti
Summary: The magnetic proximity effect is studied in EuO/Co bilayers using magneto-optical Kerr effect measurements. Excitation above EuO bandgap results in ultrafast enhancement of EuO magnetization followed by demagnetization. The superdiffusive spin current from Co into EuO is observed as well. The bilayers provide a tunable system where the magneto-optical signal can be adjusted by external parameters, and experimental evidence for the presence of a tuneable magnetic proximity coupling between Co and EuO is given by measuring the magnetic hysteresis of EuO up to room temperature.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Crystallography
Martin Mikulics, Roman Adam, Genyu Chen, Debamitra Chakraborty, Jing Cheng, Anthony Pericolo, Ivan Komissarov, Daniel E. Buergler, Sarah F. Heidtfeld, John Serafini, Stefan Preble, Roman Sobolewski, Claus M. Schneider, Joachim Mayer, Hilde H. Hardtdegen
Summary: The study fabricated and tested THz photomixer devices based on nitrogen-implanted GaAs integrated with a Bragg reflector. The material properties and any reversible or irreversible material changes were investigated using Raman spectroscopy. The results showed that degradation effects in the photomixer structures could be avoided if the total optical power density was below 0.7 mW/µm² for 100 minutes of operation. Furthermore, a reversible curing mechanism was observed if the power density level of around 0.58 mW/µm² was not exceeded.
Article
Nanoscience & Nanotechnology
Frank Volmer, Manfred Ersfeld, Paulo E. Faria Junior, Lutz Waldecker, Bharti Parashar, Lars Rathmann, Sudipta Dubey, Iulia Cojocariu, Vitaliy Feyer, Kenji Watanabe, Takashi Taniguchi, Claus M. Schneider, Lukasz Plucinski, Christoph Stampfer, Jaroslav Fabian, Bernd Beschoten
Summary: Transition metal dichalcogenides (TMDs) have the property of forming valley-polarized excitons when illuminated by circularly polarized light, which has attracted attention in valley- and spintronics. In TMD-heterostructures, a mechanism of transferring valley polarization from excitons to free charge carriers in different layers has been identified in twisted WSe2/MoSe2 heterobilayers. This mechanism has long valley lifetimes of up to 12 ns and is most efficient at large twist angles.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Multidisciplinary Sciences
Klaus M. Seemann, Andras Kovacs, Thomas E. Schmid, Katarina Ilicic, Gabriele Multhoff, Rafal E. Dunin-Borkowski, Caterina Michelagnoli, Natalia Cieplicka-Orynzak, Soumen Jana, Giacomo Colombi, Michael Jentschel, Claus M. Schneider, Bernd Kuhn
Summary: These functionalized magnetic nanoparticles show great potential for cancer treatment due to their advantageous features such as superparamagnetic and ferromagnetic properties, radiation emission, and optical visualization.
Article
Engineering, Electrical & Electronic
C. Tusche, K. Hagiwara, X. L. Tan, Y. -J. Chen, C. M. Schneider
Summary: Materials with unique quantum characteristics, known as quantum materials, have become essential for information technology. Their transportation phenomena are closely related to their electronic structure. Therefore, it is necessary to explore the electronic states and interactions in these materials to understand and design their physical behavior. In this study, we use advanced photoelectron spectroscopy approach to investigate several quantum materials and observe specific features in their electronic structures, which are caused by a progressive symmetry reduction.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Materials Science, Multidisciplinary
Claire Besson, Philipp Stegmann, Michael Schnee, Zeila Zanolli, Simona Achilli, Nils Wittemeier, Asmus Vierck, Robert Frielinghaus, Paul Koegerler, Janina Maultzsch, Pablo Ordejon, Claus M. Schneider, Alfred Hucht, Juergen Koenig, Carola Meyer
Summary: We demonstrate a concept of molecular-level spintronics by studying spin centers antiferromagnetically (AFM) coupled to result in a singlet ground state. By performing time-dependent quantum transport measurements, we observe distinct current transitions corresponding to the AFM states of individual molecular complexes grafted on a carbon nanotube. Our statistical analysis shows independent switching events for cobalt complexes and coherent superposition of AFM spin states for manganese complexes.
Article
Chemistry, Multidisciplinary
Mohammad Reza Safari, Frank Matthes, Claus M. Schneider, Karl-Heinz Ernst, Daniel E. Buergler
Summary: The interaction between chirality and magnetism has fascinated scientists for many years. Recently, chirality-induced spin selectivity has regained attention. Experimental observations have shown significant spin polarization when electron travels through layers of chiral molecules. However, the exact mechanism behind this phenomenon remains unclear.
Article
Materials Science, Multidisciplinary
Iulia Cojocariu, Silvia Carlotto, Daniel Baranowski, Matteo Jugovac, Jan Dreiser, Luca Schio, Luca Floreano, Maurizio Casarin, Vitaliy Feyer, Claus M. Schneider
Summary: This study explores the magnetic anisotropy of metal complexes and its crucial role in cutting-edge applications such as spintronics, memory storage, and quantum computing. The challenge of achieving maximum magnetic anisotropy for paramagnetic single nickel ion sites is addressed and solved through a thermally induced planarization reaction in tetraphenylporphyrin. This reaction maintains the nickel species in a square planar coordination environment and reduces the reactivity of the molecular species through increased pi-conjugation.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
M. R. Losada, A. T. Costa, B. Biel, J. Fernandez-Rossier
Summary: This study investigates the indirect exchange interactions between localized spins of magnetic impurities in spin valley coupled systems using the Kane-Mele model. The research shows that perturbation theory works well even in nonperturbative regime and explores the effects of symmetry and crystallographic direction on the indirect exchange. They also explore the potential of using indirect exchange combined with atomic manipulation to engineer specific models.