Article
Chemistry, Physical
Sumit Naskar, Vladimiro Mujica, Carmen Herrmann
Summary: Electrons moving through chiral molecules are selectively influenced by their spin orientation and the helicity of the molecule in a phenomenon called chiral-induced spin selectivity (CISS). In this study, carbon helices connected to gold electrodes were investigated using a non-equilibrium Green's function method, a Landauer approach, and density functional theory. It was found that the transmitted electrons exhibited spin polarization, which was also observed in the non-equilibrium electronic structure of the junctions. Although the spin polarization was small, its sign changed with the current direction and the handedness of the molecule. The use of computationally more expensive hybrid functionals may lead to larger spin polarization, suggesting that non-equilibrium spin polarization could be a key element in understanding the CISS mechanism.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ashima Bajaj, Rishu Khurana, Md Ehesan Ali
Summary: A stimuli-based spin filter using a photo-responsive endoperoxide (EPO) based single molecule device has been developed, with the diradical intermediate of EPO facilitating high spin filtering efficiency. The transmission characteristics of various photoproducts along the photochemical reaction pathway of EPO are investigated, demonstrating the key role of quantum interference effects in the modulation of conductance.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Physics, Applied
Teng Gao, Qipeng Tian, Mengzhao Du, Longlong Zhang, Xuan Liu, Wei Qin, Shijie Xie
Summary: In this study, we investigate the synergistic effect of carrier velocity and density in helical spin-filtering devices to understand chirality-induced spin selectivity (CISS). We reveal two types of dynamics for spin polarization and provide a general microscopic perspective for reconsidering CISS.
APPLIED PHYSICS LETTERS
(2022)
Review
Chemistry, Analytical
Nozomi Nishizawa, Hiro Munekata
Summary: Lateral-type spin-photonic devices have advantages in circularly polarized light applications including compactness, standalone nature, room temperature operation, high circular polarization emission, polarization controllability, and are widely used in various fields and potentially for biological diagnosis.
Article
Chemistry, Multidisciplinary
Thomas P. Fay, David T. Limmer
Summary: A mechanism is proposed to generate spin-polarization dynamically in chiral molecular systems during photoinduced electron transfer. This mechanism explains how spin-polarization emerges in systems with incoherent hopping for charge transport, mediated by spin-orbit and electronic exchange couplings. The theory predicts nonmonotonic temperature dependence of spin-polarization, independent of spin-orbit coupling magnitude.
Article
Chemistry, Multidisciplinary
Jingying Wang, Haipeng Lu, Xin Pan, Junwei Xu, Haoliang Liu, Xiaojie Liu, Dipak R. Khanal, Michael F. Toney, Matthew C. Beard, Z. Valy Vardeny
Summary: Research has shown that integrating chiral organic ligands into two-dimensional hybrid organic-inorganic perovskites can introduce spintronics applications, leading to spin-dependent photovoltaic and photogalvanic responses. This discovery may have potential applications in optoelectronic devices sensitive to light helicity.
Article
Chemistry, Analytical
Kaushik K. Rangharajan, Shaurya Prakash
Summary: A nanofluidic device with spatially non-uniformly distributed gate electrodes is developed for the capture and local concentration of proteins in nanochannels. The captured proteins can be released by removing the gate potential.
Article
Multidisciplinary Sciences
Sara Varotto, Annika Johansson, Boerge Goebel, Luis M. Vicente-Arche, Srijani Mallik, Julien Brehin, Raphael Salazar, Francois Bertran, Patrick Le Fevre, Nicolas Bergeal, Julien Rault, Ingrid Mertig, Manuel Bibes
Summary: Rashba interfaces have shown potential as platforms for spin-charge interconversion. We used angle resolved photoemission spectroscopy to investigate KTaO3 two-dimensional electron gases and observed their Rashba-split bands. Our calculations revealed complex spin and orbital textures, as well as interconversion efficiencies exceeding those of other oxide two-dimensional electron gases.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Artem G. Volosniev, Hen Alpern, Yossi Paltiel, Oded Millo, Mikhail Lemeshko, Areg Ghazaryan
Summary: The study reveals that a one-dimensional quantum model with both friction and spin-orbit coupling can exhibit spin polarization, even with moderate spin-orbit coupling, as long as the friction is strong. These findings help explain the impact of chirality on spin distribution and transport in chiral molecules, and suggest static magnetic properties of chiral molecules that lead to Shiba-like states on a superconductor.
Article
Chemistry, Physical
J. Fransson
Summary: This study investigates the charge and spin dynamics in chiral molecules after their immediate coupling to an external metallic reservoir. The research describes the induction of spin polarization in chiral structures as a response to charge dynamics. The dynamics show that chirality-induced spin selectivity is an excited state phenomenon that can be partially explained using a simplistic single-particle description in the transient regime, but in the stationary limit, electron correlations, such as electron-vibration interactions, are crucial in sustaining an intrinsic spin anisotropy that leads to a nonvanishing spin selectivity. Furthermore, the dynamics provide insight into enantiomer separation based on different acquired spin polarizations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Physics, Applied
Krishna Maity, Jean-Francois Dayen, Marlene Palluel, Nathalie Daro, Guillaume Chastanet, Bohdan Kundys, Bernard Doudin
Summary: Graphene films are used to detect the presence and transition of spin crossover nanoparticle aggregates. This study provides insight into the mechanism for the change of impedance and Fermi level of graphene in proximity with different states of the molecular structure, offering potential for fast molecular electronics applications.
APPLIED PHYSICS LETTERS
(2023)
Review
Chemistry, Multidisciplinary
Tanglue Feng, Zhiyu Wang, Zixuan Zhang, Jie Xue, Haipeng Lu
Summary: This MiniReview explores the significance of chiral metal-halide semiconductors in spin-dependent photonic and electronic applications, discussing their chemical and structural diversity, as well as the mechanism behind spin selectivity. Recent progress in experimental demonstrations of spin control in various photonic and spintronic devices is highlighted. Ongoing challenges and opportunities associated with chiral MHS are also discussed.
Article
Materials Science, Multidisciplinary
R. Jansen, A. Spiesser, Y. Fujita, H. Saito, S. Yamada, K. Hamaya, S. Yuasa
Summary: The spin voltages produced in lateral spin-transport devices were investigated, revealing that the signals are influenced by various factors such as spin transport of mobile carriers, spin accumulation, and local spin signals. Additionally, a clear broad Hanle signal from confined electrons was observed in the nonlocal spin signal, which was suggested to be mediated by heat flow.
Article
Chemistry, Multidisciplinary
Yaohui Li, Xiang Wu, Guangzheng Zuo, Yufei Wang, Xianjie Liu, Yanxian Ma, Bolun Li, Xu-Hui Zhu, Hongbin Wu, Jian Qing, Lintao Hou, Wanzhu Cai
Summary: Selective electron transport and extraction are crucial for photovoltaic devices. This study presents an electron transport layer (ETL) configuration composed of a solution-processed n-n organic heterojunction to enhance electron transport and boost power conversion efficiency (PCE) in organic photovoltaics (OPV). The n-n heterojunction consists of a narrow-band n-type conjugated polymer layer (PNDIT-F3N) and a wide-band n-type conjugated molecule layer (Phen-NaDPO). The performance improvement in OPVs with different active layers is attributed to selective carrier transport properties, reduced recombination, and good film-forming quality of the ETL configuration.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
J. Y. Kim, M. Samiepour, E. Jackson, J. Ryu, D. Iizasa, T. Saito, M. Kohda, J. Nitta, H. E. Beere, D. A. Ritchie, A. Hirohata
Summary: In this work, the fabrication of a Fe/n-GaAs spin injection device and the experimental setup for optical gating of the nonlocal spin transport signal were demonstrated. The results showed more uniform current distribution at the Fe/n-GaAs injector interface at bias voltages higher than the Schottky barrier height. Successful spin injection into n-GaAs was confirmed through three- and four-terminal Hanle measurements, with strong interfacial spin dephasing at high magnetic fields. Using a time-resolved pump-probe Kerr rotation setup, a modulation of the nonlocal signal (0.4 +/- 0.3)% depending on the light helicity was observed in Fe/n-GaAs lateral spin injection devices at 30 K.
Article
Multidisciplinary Sciences
Peter Dunne, Takuji Adachi, Arvind Arun Dev, Alessandro Sorrenti, Lucas Giacchetti, Anne Bonnin, Catherine Bourdon, Pierre H. Mangin, J. M. D. Coey, Bernard Doudin, Thomas M. Hermans
Article
Multidisciplinary Sciences
C. Banerjee, N. Teichert, K. E. Siewierska, Z. Gercsi, G. Y. P. Atcheson, P. Stamenov, K. Rode, J. M. D. Coey, J. Besbas
NATURE COMMUNICATIONS
(2020)
Article
Physics, Multidisciplinary
C. Banerjee, K. Rode, G. Atcheson, S. Lenne, P. Stamenov, J. M. D. Coey, J. Besbas
Summary: The study investigated the all-optical reswitching phenomenon in a half-metallic Hensler ferrimagnet, Mn2Ru0.9Ga, analyzing the optimal time between two laser pulses and the physical mechanisms involved. The results indicate that spin waves generated through optical excitation can lead to transient parallel alignment of magnetic moments after a certain time.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
Zexiang Hu, Jean Besbas, Ross Smith, Niclas Teichert, Gwenael Atcheson, Karsten Rode, Plamen Stamenov, J. M. D. Coey
Summary: Toggle switching behavior is observed in thin films of sperimagnetic amorphous DyxCo1-x and TbxCo1-x irradiated with single fast laser pulses. The films exhibit strong local random anisotropy, and subsequent laser pulses lead to partial re-switching of a decreasing amount of material, resulting in a granular structure. The toggle switching is attributed to the temperature-dependent ratio of local anisotropy to exchange.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
J. M. D. Coey, D. Givord, D. Fruchart
Summary: This article presents energy-level diagrams for cubic metallic Fe4N and Mn4N, describing their magnetic properties. The magnetic ordering and tunable ferrimagnetic compensation in Mn3-xM'N-x metallic perovskites are discussed, along with the characteristics of topological ferrimagnets. The article emphasizes the wide range of applications in magnetic structures, magnetotransport, magnetocaloric, and magnetovolume effects in metallic perovskites.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2022)
Article
Mechanics
Sruthy Poulose, Jennifer A. Quirke, Plamen Stamenov, Matthias E. Mobius, J. M. D. Coey
Summary: In this study, pendant droplets of water and paramagnetic solutions were examined in the presence of uniform and nonuniform magnetic fields. The findings showed that the surface tension of water droplets was minimally affected by a uniform magnetic field, while the magnetic field gradient was able to deform the droplets and affect their density. The dynamic measurements revealed that the magnetic field had no significant impact on the pinch-off dynamics.
Article
Physics, Applied
Jinu Kurian, Aleena Joseph, Salia Cherifi-Hertel, Ciaran Fowley, Gregor Hlawacek, Peter Dunne, Michelangelo Romeo, Gwenael Atcheson, J. M. D. Coey, Bernard Doudin
Summary: He+ ion irradiation is used to pattern multiple areas of Pt/Co/W films with different irradiation doses in Hall bars, resulting in a landscape of perpendicular magnetic anisotropy. This enables selective multilevel current-induced switching, with full control of the position and order of the individual switching elements. Key pattern design parameters are specified, offering a scalable approach for multilevel switching devices.
APPLIED PHYSICS LETTERS
(2023)
Review
Physics, Condensed Matter
Tim A. Butcher, J. M. D. Coey
Summary: This article provides an overview of the effect of a magnetic field gradient on fluids with linear magnetic susceptibilities. It shows the equivalence between the magnetic field gradient force and the concentration gradient force for paramagnetic species in solution in incompressible fluids. The magnetic field gradient and concentration gradient forces are approximations of the Kelvin force and Korteweg-Helmholtz force densities, respectively. The criterion for the appearance of magnetically induced convection is derived, and experimental work involving magnetically induced convection is reviewed.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Applied
Yangkun He, J. M. D. Coey, Zsolt Gercsi
Summary: Fully compensated ferrimagnetic half metals have attracted great attention in spintronics. Unlike previous calculations based on hypothetical ordered alloys, we investigated existing solid solution series using Co1-xCrxS2 as an example. Our calculations reveal a low-spin state for Cr, consistent with early experiments, and a fully compensated ferrimagnetic half metal with a Curie temperature above room temperature at x approximate to 0.33. This study demonstrates the method of combining two half metals with light and heavy 3d metals in a solid solution to achieve compensation, where atomic disorder does not compromise the desired properties.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
K. E. Siewierska, H. Kurt, B. Shortall, A. Jha, N. Teichert, G. Atcheson, M. Venkatesan, J. M. D. Coey, Z. Gercsi, K. Rode
Summary: The cubic Heusler alloy Ru2-xMn1+xAl, grown as a thin film on MgO and MgAl2O4 substrates, is a spin-polarised ferrimagnetic metal with weak magnetocrystalline anisotropy. Unlike Mn2RuxGa, it does not exhibit ferrimagnetic compensation or large magneto-galvanic effects, which are attributed to a combination of atomic order and hybridisation with the group 13 element Al or Ga. The spin polarisation is around 50% to 60%, with a gap in the density of states just above the Fermi level in fully ordered compounds.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Editorial Material
Physics, Multidisciplinary
Zsolt Gercsi, Yangkun He, J. M. D. Coey
PHYSICAL REVIEW LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Sruthy Poulose, Yara Alvarez-Brana, Lourdes Basabel-Desmonts, Fernando Benito-Lopez, John Michael David Coey
Summary: Water evaporation is studied in confined environments, and it is found that the magnetic field has a greater effect on the evaporation rate in microchannels compared to beakers. The evaporation rate in microchannels is double that of beakers, but lower than expected for an open surface in still air. The magnetic enhancement is due to the gradient of the applied magnetic field, which affects the isomeric populations in the vapor and increases the evaporation rate.
IEEE MAGNETICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Yangkun He, Simon Lenne, Zsolt Gercsi, Gwenael Atcheson, Jack O'Brien, Daniel Fruchart, Karsten Rode, J. M. D. Coey
Summary: This article investigates the spin structure of Mn4N films and its influence on the magnetotransport properties.
Article
Materials Science, Multidisciplinary
K. E. Siewierska, G. Atcheson, A. Jha, K. Esien, R. Smith, S. Lenne, N. Teichert, J. O'Brien, J. M. D. Coey, P. Stamenov, K. Rode
Summary: The ruthenium content in half-metallic Mn2RuxGa thin films plays a crucial role in determining their magnetic and electronic properties. The study reveals that chemical disorder exists for all compositions, and increasing Mn or Ru content affects the magnetic behavior and spin polarization. The systematic investigation of physical properties as a function of x and y could guide the selection of compositions for magnonic and spintronic MRG-based devices.
Article
Materials Science, Multidisciplinary
Rui Zhang, Zsolt Gercsi, M. Venkatesan, Karsten Rode, J. M. D. Coey
Summary: Calculations suggest that ordered Heusler alloys with 18 valance electrons could exhibit a variety of unusual electronic and magnetic states. Experimental results show that the as-cast alloys are all Pauli paramagnets with some degree of B2-type ordering, and prolonged annealing leads to phase segregation. Density functional theory calculations confirm that different atomic arrangements in the interpenetrating face-centered cubic sublattices could lead to unusual magnetic properties, but disorder destroys both magnetism and semiconductivity.