Article
Materials Science, Multidisciplinary
Olivier Rousseau, Cosimo Gorini, Fatima Ibrahim, Jean-Yves Chauleau, Aurelie Solignac, Ali Hallal, Sebastian Toelle, Mairbek Chshiev, Michel Viret
Summary: Both theoretically and experimentally, it has been demonstrated that a Rashba-split electron state inside a ferromagnet can efficiently convert dynamic spin accumulation into electrical voltage. This effect, associated with the symmetry linked to the magnetization direction, has been measured through spin pumping in a CoFeB vertical bar MgO structure, showing comparable efficiency to the inverse spin Hall effect without affecting the magnetic damping in the ferromagnet.
Article
Chemistry, Multidisciplinary
Annalena Gaertner, Lukas Meier, Merle Arrowsmith, Maximilian Dietz, Ivo Krummenacher, Ruediger Bertermann, Felipe Fantuzzi, Holger Braunschweig
Summary: The stepwise reduction of a doubly cyclic alkyl(amino)carbene (CAAC)-stabilized 2,3-bis(dibromoboryl)naphthalene enables the isolation of various organic compounds, including boryl radicals, diborete, and cyclic bis(alkylidene)diboron dianion. The diborete exhibits biradical character and a highly strained structure.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
David M. Mahler, Valentin L. Mueller, Cornelius Thienel, Jonas Wiedenmann, Wouter Beugeling, Hartmut Buhmann, Laurens W. Molenkamp
Summary: Magneto-transport measurements on gated high-mobility heterostructures containing a 60 nm layer of tensile-strained HgTe reveal the presence of well-developed Hall quantization from surface states in both n- and p-type regimes. While the n-type behavior is attributed to transport in the topological surface state, the p-type transport is shown to result from massive Volkov-Pankratov states, preventing the observation of the p-conducting topological surface state in transport experiments.
Article
Physics, Applied
Dapeng Zhu, Yi Wang, Shuyuan Shi, Kie-Leong Teo, Yihong Wu, Hyunsoo Yang
Summary: The study focused on the SOT efficiency of Bi2Se3/Fe heterostructures, showing that in situ fabrication methods exhibit higher efficiency below 100K compared to ex situ methods, largely due to a thinner interfacial layer and enhanced interface spin transparency.
APPLIED PHYSICS LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Rui Yu, Jie Feng Cao, Xiang Yu Meng, Fang Yuan Zhu, Jun Qin Li, Ge Xing Qu, Yao Bo Huang, Yong Wang, Ren Zhong Tai
Summary: This study demonstrates the controllable charge-spin conversion efficiency in topological insulators by manipulating the ferroelectric polarization, with an enhancement of up to about 450%. The efficiency is mainly influenced by the evolution of the band structure under strain modulation.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Van Tuong Pham, Maxen Cosset-Cheneau, Ariel Brenac, Olivier Boulle, Alain Marty, Jean-Philippe Attane, Laurent Vila
Summary: In this study, we measured the spin-charge interconversion using the spin Hall effect in various ferromagnetic/Pt nanodevices, and found that interface resistance and spin polarization play crucial roles in spin injection/detection. Additionally, we showed that interfacial asymmetric spin scattering becomes the dominant mechanism of spin injection in our samples.
Article
Materials Science, Multidisciplinary
L. L. Tao, Evgeny Y. Tsymbal
Summary: Recent research on current-induced spin polarization has been reinvigorated by the discovery of this phenomenon in some emerging materials. The study found that the anisotropic response of CISP to the current direction depends strongly on the type of spin-orbit coupling. Additionally, CISP is nonlinear with respect to the SOC magnitude, dependent on the Fermi energy, and exhibits different transport regimes for low or high carrier density.
Article
Engineering, Environmental
Saeid Akrami, Yasushi Murakami, Monotori Watanabe, Tatsumi Ishihara, Makoto Arita, Qixin Guo, Masayoshi Fuji, Kaveh Edalati
Summary: This study successfully overcomes the limitations of bismuth vanadate (BiVO4) in photocatalytic CO2 conversion by introducing oxygen vacancies and lattice strain, leading to a low recombination rate, enhanced conduction band level, and narrowed bandgap. The oxygen-deficient and highly-strained BiVO4 exhibits a high photocatalytic CO2 conversion rate comparable to that of the P25 TiO2 photocatalyst. The enhancement of photocatalytic activity is attributed to the modification of the band structure, enhanced light absorbance, prolonged lifetime of excited electrons, and the utilization of oxygen vacancies as activation sites for CO2 photoreduction.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Physics, Condensed Matter
Nigel Lee En Hew, Dino Spagnoli, Lorenzo Faraone
Summary: The study uses density functional theory to investigate the core structure energetics of partial dislocations in HgTe, CdTe, and Hg0.7Cd0.3Te, and the density of states of these dislocations in CdTe and Hg0.7Cd0.3Te. Stable dislocation pairs were found for both 30 degrees and 90 degrees partial dislocations, with energetically favorable segregation of Hg atoms to the dislocation cores in Hg0.7Cd0.3Te. The 90 degrees partial dislocations were found to introduce more mid-gap states compared to the 30 degrees partial dislocations in CdTe and Hg0.7Cd0.3Te, suggesting a greater detrimental effect on the material's optoelectronic properties.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Naoya Arakawa, Kenji Yonemitsu
Summary: The authors model a periodically driven t2g-orbital metal and demonstrate how the spin Hall and anomalous Hall effects are realized and can be distinguished by their response to circularly polarized light with different helicities. This difference is protected by the symmetry of a time reversal operation, and the findings offer a way to distinguish the spin current and charge current via light.
COMMUNICATIONS PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Federico Binda, Stefano Fedel, Santos Francisco Alvarado, Paul Noel, Pietro Gambardella
Summary: The study investigates the spin-orbit torques (SOTs) and spin Hall magnetoresistance generated by Bi0.9Sb0.1(0001) when coupled with FeCo, confirming its effectiveness as a spin-injector material. The research finds that charge-to-spin conversion in single-crystal Bi0.9Sb0.1(0001) is isotropic despite the strong anisotropy of the topological surface states. Additionally, the damping-like SOT displays non-monotonic temperature dependence, with a minimum occurring at 20 K.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
E. Rongione, L. Baringthon, D. She, G. Patriarche, R. Lebrun, A. Lemaitre, M. Morassi, N. Reyren, M. Micica, J. Mangeney, J. Tignon, F. Bertran, S. Dhillon, P. Le Fevre, H. Jaffres, J. -m. George
Summary: By combining spin- and angle-resolved photoemission spectroscopy with time-resolved THz emission spectroscopy, it is demonstrated that spin-charge conversion mainly arises from the surface state in ultrathin films of Bi1-xSbx. The robustness of the surface state and the significant conversion efficiency in epitaxial Bi1-xSbx thin films bring new perspectives for ultra-low power magnetic random-access memories and broadband THz generation.
Article
Materials Science, Multidisciplinary
Van Tuong Pham, Haozhe Yang, Won Young Choi, Alain Marty, Inge Groen, Andrey Chuvilin, F. Sebastian Bergeret, Luis E. Hueso, Ilya V. Tokatly, Felix Casanova
Summary: Spin-charge interconversion plays a crucial role in systems, and we experimentally demonstrate that the inverse spin galvanic effect at metal interfaces has a significant impact on spin-charge interconversion, rather than the spin Hall effect in bulk metals. Using two parameters to quantify spin-charge interconversion is an effective approach.
Article
Optics
Bei Yan, Yuchen Peng, Aoqian Shi, Jianlan Xie, Peng Peng, Jianjun Liu
Summary: This research explores the topological edge states and topological corner states formed by domain walls between different symmetric structures and verifies the realization of these states. The results have important implications for connecting waveguides with different symmetries to construct optical communication devices.
Article
Materials Science, Multidisciplinary
E. Rongione, S. Fragkos, L. Baringthon, J. Hawecker, E. Xenogiannopoulou, P. Tsipas, C. Song, M. Micica, J. Mangeney, J. Tignon, T. Boulier, N. Reyren, R. Lebrun, P. Le Fevre, S. Dhillon, A. Dimoulas, H. Jaffres, M. George
Summary: This study demonstrates sizable terahertz (THz) emission through a nanometric thick topological insulator (TI)/ferromagnetic junction. By employing terahertz emission time domain spectroscopy (TDS), the contribution of topological surface states (TSS) to spin-to-charge conversion (SCC) is investigated, highlighting the significance of this approach for studying interfacial spintronic properties.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Colum M. O'Leary, Benedikt Haas, Christoph T. Koch, Peter D. Nellist, Lewys Jones
Summary: The article presents an extension of existing STEM distortion correction techniques for the treatment of 4D data series, demonstrating improvements in spatial fidelity, signal-to-noise ratio (SNR), phase precision, and spatial resolution using electron ptychography and electric-field mapping as model cases.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Georg Schoenweger, Adrian Petraru, Md Redwanul Islam, Niklas Wolff, Benedikt Haas, Adnan Hammud, Christoph Koch, Lorenz Kienle, Hermann Kohlstedt, Simon Fichtner
Summary: This paper presents the first in-depth structural and electrical characterization of all-epitaxial, all-wurtzite-type ferroelectric III-N semiconductor heterostructures. The results show that Al1-xScxN films have multiple strain states and exhibit splitting of the ferroelectric displacement current into separate peaks. It is also observed that films grown on the metal-polar GaN template feature an initial multidomain state.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Physics, Applied
A. Sidi El Valli, V. Iurchuk, G. Lezier, I. Bendjeddou, R. Lebrun, N. Lamard, A. Litvinenko, J. Langer, J. Wrona, L. Vila, R. Sousa, I. L. Prejbeanu, B. Dieny, U. Ebels
Summary: In this study, the rectified output dc voltage of spintronic rf detectors was optimized by adjusting the properties of the magnetic tunnel junctions (MTJs). The results showed that the size and shape of the MTJ have a significant impact on the rectified signal, and reducing the diameter and thickness of the free layer can greatly enhance the rectification effect.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Nitu Syed, Alastair Stacey, Ali Zavabeti, Chung Kim Nguyen, Benedikt Haas, Christoph T. Koch, Daniel L. Creedon, Enrico Della Gaspera, Philipp Reineck, Azmira Jannat, Matthias Wurdack, Sarah E. Bamford, Paul J. Pigram, Sherif Abdulkader Tawfik, Salvy P. Russo, Billy J. Murdoch, Kourosh Kalantar-Zadeh, Chris F. McConville, Torben Daeneke
Summary: In this study, ultrathin indium nitride nanosheets were synthesized using a liquid metal-based printing method and a microwave plasma-enhanced nitridation reaction. The nanosheets exhibited high carrier mobilities and quantized states, making them promising for applications in optoelectronic devices and 2D heterostructures.
Article
Chemistry, Multidisciplinary
Yu Fu, Jing Li, Jules Papin, Paul Noel, Salvatore Teresi, Maxen Cosset-Cheneau, Cecile Grezes, Thomas Guillet, Candice Thomas, Yann-Michel Niquet, Philippe Ballet, Tristan Meunier, Jean-Philippe Attane, Albert Fert, Laurent Vila
Summary: Spin-orbit effects in topological insulators and at Rashba interfaces have led to various newly discovered effects. In this study, a bilinear magnetoresistance phenomenon was observed in strained HgTe, and its amplitude and sign could be controlled by adjusting the contributions from opposite surfaces using an electric gate.
Article
Optics
S. Gebert, C. Consejo, S. S. Krishtopenko, S. Ruffenach, M. Szola, J. Torres, C. Bray, B. Jouault, M. Orlita, X. Baudry, P. Ballet, S. V. Morozov, V. I. Gavrilenko, N. N. Mikhailov, S. A. Dvoretskii, F. Teppe
Summary: Since the emergence of graphene, proposals for tunable Landau lasers in the terahertz frequency range have been made. Despite the non-equidistance of the Landau levels, a non-radiative process still persists in Landau-quantized graphene. This work demonstrates Landau emission from Dirac fermions in HgTe quantum wells, which can be tuned by both magnetic field and carrier concentration.
Article
Materials Science, Multidisciplinary
Dhananjay Tiwari, Martin Christoph Scheuerlein, Mahdi Jaber, Eric Gautier, Laurent Vila, Jean-Philippe Attane, Michael Schoebitz, Aurelien Masseboeuf, Tim Hellmann, Jan P. Hofmann, Wolfgang Ensinger, Olivier Fruchart
Summary: We investigated the properties of (NixCo1-x)B ferromagnetic nanotubes with azimuthal magnetization. The tubes were fabricated using electroless plating in polycarbonate porous templates, with lengths of several tens of micrometers, diameters ranging from 100 nm to 500 nm, and wall thicknesses from 10 nm to 80 nm. The resistivity was found to be approximately 1.5 x 10(-6) Omega m, and the anisotropic magnetoresistance (AMR) was 0.2 to 0.3%, indicating a dependence on grain boundaries. The azimuthal anisotropy field was determined from M(H) AMR loops of single tubes and was around 10mT, showing a tendency to increase with wall thickness and Co content, but not significantly affected by diameter or curvature.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Benedikt Haas, Tara M. Boland, Christian Elsaesser, Arunima K. Singh, Katia March, Juri Barthel, Christoph T. Koch, Peter Rez
Summary: Phonon scattering at grain boundaries plays a crucial role in controlling the thermal conductivity of nanoscale devices. This study uses monochromated electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) to measure the 60 meV optic mode at grain boundaries in silicon at atomic resolution. The results show the existence of localized phonon modes and support the idea that grain boundaries can act as waveguides.
Article
Multidisciplinary Sciences
Cecile Grezes, Aurelie Kandazoglou, Maxen Cosset-Cheneau, Luis M. Vicente Arche, Paul Noel, Paolo Sgarro, Stephane Auffret, Kevin Garello, Manuel Bibes, Laurent Vila, Jean-Philippe Attane
Summary: A central goal of spintronics is to control magnetism electrically. Spin-orbit torques (SOTs) have provided a new way to manipulate magnetization using in-plane current. This study demonstrates the non-volatile electric-field control of SOTs in oxide-based Rashba-Edelstein 2DEG, offering switchable states with a large resistance contrast. These findings validate the compatibility of oxide 2DEGs for magnetic tunnel junction integration and pave the way for electrically reconfigurable SOT MRAMS circuits and other devices.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
P. B. Veiga, A. Mora-Hernandez, M. Dammak, S. Auffret, I. Joumard, L. Vila, Liliana D. Buda-Prejbeanu, I. L. Prejbeanu, B. Dieny, R. C. Sousa
Summary: This study reports on the low temperature characteristics of optimized magnetic tunnel junctions for cryogenic operation. The magnetic and electrical properties of four different structures were characterized, with insertions of Mg, Ru, and permalloy (Py) to reduce the effective anisotropy of the storage layer. A Py insertion layer resulted in higher figures of merit (FOM), with an FOM of 3.78k(B)T(op)/mu A and switching energy E-sw below 655 fJ for devices operating at T-op = 10 K. Additionally, a method to optimize the reference layer stray field was implemented for 20 nm diameter devices using a synthetic antiferromagnetic layer for full compensation.
Article
Chemistry, Multidisciplinary
Salvatore Teresi, Nicolas Sebe, Jessy Patterson, Theo Frottier, Aurelie Kandazoglou, Paul Noel, Paolo Sgarro, Damien Terebenec, Nicolas Bernier, Francoise Hippert, Jean-Philippe Attane, Laurent Vila, Pierre Noe, Maxen Cosset-Cheneau
Summary: Driving a spin-logic circuit requires a large output signal generated by spin-charge interconversion in spin-orbit readout devices. However, obtaining high-quality topological insulators compatible with conventional industrial deposition processes remains challenging. In this study, a spin-orbit readout device made of the topological insulator Sb2Te3 deposited by large-scale industrial magnetron sputtering on SiO2 is fabricated, and a significant output voltage attributed to spin-charge interconversion is measured. These results offer a path towards integrating layered van der Waals materials in spin-logic devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Federico Binda, Stefano Fedel, Santos Francisco Alvarado, Paul Noel, Pietro Gambardella
Summary: The study investigates the spin-orbit torques (SOTs) and spin Hall magnetoresistance generated by Bi0.9Sb0.1(0001) when coupled with FeCo, confirming its effectiveness as a spin-injector material. The research finds that charge-to-spin conversion in single-crystal Bi0.9Sb0.1(0001) is isotropic despite the strong anisotropy of the topological surface states. Additionally, the damping-like SOT displays non-monotonic temperature dependence, with a minimum occurring at 20 K.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xuefeng Pan, Rongying Liu, Zhilong Yu, Benedikt Haas, Zdravko Kochovski, Sijia Cao, Radwan M. Sarhan, Guosong Chen, Yan Lu
Summary: This research presents a facile and green approach for the synthesis of metal/carbon nanotube (CNT) composites using a versatile glycopeptide (GP) as a stabilizer for CNTs and a reducing agent for noble metal ions. The formed GP-CNTs exhibit excellent plasticity, enabling the availability of various forms of CNT species. The metal nanoparticles can be immobilized on the CNT surface at room temperature without additional reducing agents. The Pd/CNT composite shows promising catalytic activity for the degradation of organic pollutants, enhanced by the photothermal conversion capability of CNTs.
Article
Chemistry, Multidisciplinary
Xuefeng Pan, Rongying Liu, Zhilong Yu, Benedikt Haas, Zdravko Kochovski, Sijia Cao, Radwan M. Sarhan, Guosong Chen, Yan Lu
Summary: This study reports a facile and green approach for the fabrication of metal/CNT composites using a versatile glycopeptide (GP) as a stabilizer for CNTs in water and as a reducing agent for noble metal ions. The abundant hydrogen bonds in GP endow the formed GP-CNTs with excellent plasticity, enabling the availability of polymorphic CNT species from dispersion to viscous paste, gel, and even to dough by increasing their concentration. The GP molecules can reduce metal precursors at room temperature without additional reducing agents, enabling the in situ immobilization of metal nanoparticles (e.g. Au, Ag, Pt, and Pd) on the CNT surface. The Pd/CNT composite, which combines the excellent catalytic properties of Pd particles with the photothermal conversion capability of CNTs, shows promise as a catalyst for the fast degradation of organic pollutants.
