Article
Chemistry, Multidisciplinary
Hamas Tahir, Naresh Eedugurala, Sheng-Ning Hsu, Paramasivam Mahalingavelar, Brett M. Savoie, Bryan W. Boudouris, Jason D. Azoulay
Summary: Open-shell conjugated polymers (CPs) offer new opportunities for emerging technologies due to their unique electronic and spin structures. In this study, the connections between molecular, electronic, and solid-state transport in a high-spin donor-acceptor CP were investigated. It was found that a giant negative magnetoresistance (MR) was achieved in the CP thin-film device at low temperatures, surpassing the performance of all other organic materials. As the temperature increased, the negative MR decreased and became positive, which correlated with the electronic and spin structure of the CP.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yang Qin, Xianrong Gu, Yixiao Zhang, Shunhua Hu, Ankang Guo, Rui Zhang, Ke Meng, Tingting Yang, Cheng Zhang, Shuhang Lu, Xueli Yang, Lidan Guo, Xiangwei Zhu, Jianqi Zhang, Kun Lu, Zhixiang Wei, Xiangnan Sun
Summary: Molecular spin-photovoltaic device (MSP) integrates photovoltaic and spintronic functionalities and can modulate output signal, even achieving full spin polarization at room temperature using photo-generated voltage (Vph). To improve MSP performance, it is crucial to enhance Vph by increasing effective spin transport capability. However, the weak driving force of spin-photovoltaic interaction limits Vph's ability to modulate spin signal in current single-component MSP. In this study, an incomplete hetero-structure active layer is employed for the first time to construct a novel-designed MSP, leading to a more efficient working mechanism and greater potential for MSP in the future.
Article
Chemistry, Multidisciplinary
Shunhua Hu, Wei Liu, Lidan Guo, Rui Zhang, Xianrong Gu, Ke Meng, Yang Qin, Ankang Guo, Tingting Yang, Cheng Zhang, Xueli Yang, Shuhang Lu, Meng Wu, Kun Lu, Ting Tan, Erjun Zhou, Zhixiang Wei, Xiangnan Sun
Summary: In this study, an innovative spin-filtering-competition mechanism is proposed to continuously modulate the interfacial effect in molecular spin valves at room temperature. By precisely controlling lithium fluoride coverage on the cobalt surface, continuous modulation of the spin-injection process can be successfully achieved, allowing active control of spin polarization of the injected current and magnetoresistance effect.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Josep Ingla-Aynes, Franz Herling, Jaroslav Fabian, Luis E. Hueso, Felix Casanova
Summary: The ultimate goal of spintronics is to achieve electrically controlled coherent manipulation of electron spin at room temperature for devices such as spin field-effect transistors. The use of 2D materials with strong spin anisotropy and valley character provides unique control knobs for manipulating spin precession. Experimental results have shown successful coherent spin precession in the absence of an external magnetic field, even in the diffusive regime, by manipulating spin-orbit coupling in bilayer graphene.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Andreas Gottscholl, Matthias Diez, Victor Soltamov, Christian Kasper, Andreas Sperlich, Mehran Kianinia, Carlo Bradac, Igor Aharonovich, Vladimir Dyakonov
Summary: The research team successfully realized coherent control of ensembles of boron vacancy centers in hexagonal boron nitride (hBN) and measured the spin characteristics at different temperatures. They proposed a method to substantially reduce the magnetic resonance linewidth, providing important insights for the employment of van der Waals materials in quantum technologies.
Article
Materials Science, Multidisciplinary
Oliver Busch, Boerge Goebel, Ingrid Mertig
Summary: The spin Hall effect is typically associated with spin-orbit interaction, but it can also occur in specific materials even in absence of spin-orbit coupling. Coplanar kagome antiferromagnets Mn3X are interesting candidates for applications involving spin currents. The main contribution to the intrinsic spin Hall signal in these materials comes from noncollinear magnetic texture and is most significant in coplanar systems. Furthermore, spin-orbit coupling or out-of-plane tilting of magnetic moments can effectively reduce the spin Hall effect.
Article
Chemistry, Multidisciplinary
Gregory M. Stephen, Aubrey T. Hanbicki, Timo Schumann, Jeremy T. Robinson, Manik Goyal, Susanne Stemmer, Adam L. Friedman
Summary: The research demonstrates robust spin transport in Cd3As2 films with long spin-coherence lengths and high spin diffusion lengths, which are essential steps towards realizing spintronic devices.
Article
Multidisciplinary Sciences
B. G. Markus, M. Gmitra, B. Dora, G. Csosz, T. Feher, P. Szirmai, B. Nafradi, V. Zolyomi, L. Forro, J. Fabian, F. Simon
Summary: Graphite's electron spins dynamics presents an unexpected behavior, with the longitudinal (T-1) and transverse (T-2) relaxation times being markedly different. Injected spins with perpendicular polarization have an extraordinarily long lifetime of 100 ns at room temperature, ten times longer than the best graphene samples. This suggests that thin films of graphite or multilayer AB graphene stacks can be excellent platforms for spintronics applications compatible with 2D van der Waals technologies.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Zhen Wu, Meizhen Jiang, Jiaxing Guo, Qing Yang, Yuanyuan Zhang, Tianqing Jia, Zhenrong Sun, Donghai Feng
Summary: Electron spin dynamics in Ga-doped ZnO single crystals were studied using time-resolved Faraday and Kerr rotation spectroscopies, revealing long-lived spin coherence with two dephasing processes. The room-temperature long-lived spin signal is attributed to localized electrons, and the spin dephasing processes are found to originate from two types of localized electrons dominated by the anisotropic exchange Dzyaloshinskii-Moriya interaction.
Article
Physics, Applied
Xin Chen, Duo Wang, Linyang Li, Biplab Sanyal
Summary: In this study, we propose the theoretical predictions of a two-dimensional collinear antiferromagnetic semimetal, CrO, which exhibits remarkable spin-split band structure, spin-momentum locked transport properties, and high Neel temperature. By manipulating the position of spin-polarized anisotropic Weyl points with strain, we demonstrate the possibility of achieving four different antiferromagnetic spintronic states with zero net magnetic moments. These findings provide a new avenue in spintronics without net magnetic moment or strong spin-orbit coupling and have the potential for spintronic applications in antiferromagnetic materials.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xueli Yang, Ankang Guo, Lidan Guo, Yunqi Liu, Xiangnan Sun, Yunlong Guo
Summary: This article summarizes the basic operating principle and mechanism of organic spin valves (OSVs) and discusses the importance of accomplishing room-temperature spin transport, FM electrode selection, and spinterface. The state-of-the-art progress of organic semiconductors (OSCs) with room-temperature spin transport in spin valves is reviewed. Furthermore, the effects of carrier mobility and spin relaxation time on the spin diffusion length are systematically analyzed. A feasible perspective for improving the spin transport properties of OSCs is presented.
ACS MATERIALS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Haoshen Ye, Lisha Liu, Dongmei Bai, G. P. Zhang, Junting Zhang, Jianli Wang
Summary: In this study, the spin valve effect in the TiCr2N4 monolayer was investigated using density functional theory and Boltzmann transport theory. The results showed that the TiCr2N4 monolayer retains a ferromagnetic ground state above room temperature, and its electrical transport property is strongly dependent on the angle of magnetization direction. The large difference in conductivity between the TiCr2N4 monolayers with parallel and anti-parallel magnetization leads to giant magnetoresistance.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Yue Zhao, Xingchi Mu, Gaoyang Gou, Jian Zhou, Xiaoli Lu, Yue Hao
Summary: This study demonstrates the possibility of optical generation and nonvolatile control of pure spin photocurrent in a ferroelectric semiconductor perovskite material through theoretical calculations and optical response simulations. The findings are important for information processing and novel device designs in the field of semiconductor spintronics.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Haiyang Pan, Chusheng Zhang, Jiayu Shi, Xueqi Hu, Naizhou Wang, Liheng An, Ruihuan Duan, Pritam Deb, Zheng Liu, Weibo Gao
Summary: In this study, we demonstrate the potential of the Fe3GaTe2/graphene vdW heterostructure for room-temperature spintronic devices through the construction of graphene lateral spin valve devices. The nonlocal spin valve signals in this device are observed even at 320K, and the Fe3GaTe2 material is shown to be a promising candidate for room-temperature vdW spintronic devices due to its robust perpendicular magnetic anisotropy property.
ACS MATERIALS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Jack B. Collings, Ricardo Rama-Eiroa, Ruben M. Otxoa, Richard F. L. Evans, Roy W. Chantrell
Summary: We propose a general approach to calculate the effective anisotropy field for magnetic spins based on the Landau-Lifshitz-Gilbert equation. This approach is applicable to all orders of anisotropies, including higher-order combinations often found in functional magnetic materials. The anisotropies are represented in terms of spherical harmonics, allowing for rational temperature scaling and providing a unified framework for numerical simulations.
Article
Physics, Applied
Jan E. Stehr, Mattias Jansson, Detlev M. Hofmann, Jihyun Kim, Stephen J. Pearton, Weimin M. Chen, Irina A. Buyanova
Summary: The study investigates the electronic structure of Cr3+ in β-Ga2O3 through magneto-photoluminescence and electron paramagnetic resonance, confirming the origin of PL lines and measuring the zero-field splitting of the ground state and g-values of the first excited state.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Kai Xu, Tero-Petri Ruoko, Morteza Shokrani, Dorothea Scheunemann, Hassan Abdalla, Hengda Sun, Chi-Yuan Yang, Yuttapoom Puttisong, Nagesh B. Kolhe, Jose Silvestre Mendoza Figueroa, Jonas O. Pedersen, Thomas Ederth, Weimin M. Chen, Magnus Berggren, Samson A. Jenekhe, Daniele Fazzi, Martijn Kemerink, Simone Fabiano
Summary: The polarity change of the Seebeck coefficient in highly doped polymers is found to be the result of filling and opening of a hard Coulomb gap in the density of states. The formation of multiply charged species and the opening of this hard Coulomb gap are responsible for the inversion of the Seebeck coefficient and the decrease in electrical conductivity. These findings have implications for the molecular design of next-generation conjugated polymers.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Correction
Multidisciplinary Sciences
Chi-Yuan Yang, Marc-Antoine Stoeckel, Tero-Petri Ruoko, Han-Yan Wu, Xianjie Liu, Nagesh B. Kolhe, Ziang Wu, Yuttapoom Puttisong, Chiara Musumeci, Matteo Massetti, Hengda Sun, Kai Xu, Deyu Tu, Weimin M. Chen, Han Young Woo, Mats Fahlman, Samson A. Jenekhe, Magnus Berggren, Simone Fabiano
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Mattias Jansson, Fumitaro Ishikawa, Weimin M. Chen, Irina A. Buyanova
Summary: This study demonstrates the significant enhancement of energy upconversion efficiency in semiconductor nanowires through the design of core/shell heterostructures. The efficiency is increased by 500 times compared to the constituent materials, even under low excitation power.
Article
Multidisciplinary Sciences
Tiankai Zhang, Feng Wang, Hak-Beom Kim, In-Woo Choi, Chuanfei Wang, Eunkyung Cho, Rafal Konefal, Yuttapoom Puttisong, Kosuke Terado, Libor Kobera, Mengyun Chen, Mei Yang, Sai Bai, Bowen Yang, Jiajia Suo, Shih-Chi Yang, Xianjie Liu, Fan Fu, Hiroyuki Yoshida, Weimin M. Chen, Jiri Brus, Veaceslav Coropceanu, Anders Hagfeldt, Jean-Luc Bredas, Mats Fahlman, Dong Suk Kim, Zhangjun Hu, Feng Gao
Summary: This study proposes a new doping strategy for perovskite solar cells, using stable organic radicals as dopants and ionic salts as doping modulators. The strategy improves the performance and stability of the devices and could inspire further optimization in other optoelectronic devices.
Article
Chemistry, Physical
Bin Zhang, Johan Klarbring, Fuxiang Ji, Sergei Simak, Igor A. Abrikosov, Feng Gao, Galyna Yu Rudko, Weimin M. Chen, Irina A. Buyanova
Summary: Phonon-phonon and electron/exciton-phonon coupling are found to play a vital role in the thermal, electronic, and optical properties of metal halide perovskites. Our study focuses on the evaluation of phonon anharmonicity and coupling between electronic and vibrational excitations in the novel material, Cs2NaFeCl6, through Raman measurements and theoretical calculations. The results highlight the significance of phonon-phonon and electron-phonon interactions in the electronic properties of Cs2NaFeCl6.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Applied
Y. Q. Huang, V Polojarvi, A. Aho, R. Isoaho, T. Hakkarainen, M. Guina, I. A. Buyanova, W. M. Chen
Summary: This study demonstrates the existence of nonlinear spin response in nonmagnetic materials and showcases it in a (Ga, N)As-InAs quantum dot coupled all-semiconductor nanostructure. The observed spin nonlinearity can be conveniently tuned with an external magnetic field and potentially operates at a speed exceeding 1 GHz.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Applied
Kaito Nakama, Mitsuki Yukimune, Naohiko Kawasaki, Akio Higo, Satoshi Hiura, Akihiro Murayama, Mattias Jansson, Weimin M. Chen, Irina A. Buyanova, Fumitaro Ishikawa
Summary: This study reports the growth of GaAs/GaInNAs/GaAs core-multishell nanowires with a triple quantum-well structure. The nanowires were grown via selective area plasma-assisted molecular beam epitaxy and exhibited finely controlled structures and targeted nitrogen concentrations.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Fuxiang Ji, Johan Klarbring, Bin Zhang, Feng Wang, Linqin Wang, Xiaohe Miao, Weihua Ning, Muyi Zhang, Xinyi Cai, Babak Bakhit, Martin Magnuson, Xiaoming Ren, Licheng Sun, Mats Fahlman, Irina A. Buyanova, Weimin M. Chen, Sergei I. Simak, Igor A. Abrikosov, Feng Gao
Summary: Lead-free halide double perovskites (HDPs) have been synthesized with remarkable and fully reversible thermochromism. The thermochromism in Cs2NaFeCl6 is attributed to electron-phonon coupling, and it exhibits higher temperature sensitivity compared to lead halide perovskites and conventional semiconductors. The Cs2NaFeCl6 single crystal shows excellent environmental, thermal, and thermochromic cycle stability. This study provides valuable insights and new possibilities for developing efficient thermochromic materials.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Bin Zhang, Yuqing Huang, Fuxiang Ji, Xiaohe Miao, Feng Gao, Weimin M. Chen, Irina A. Buyanova
Summary: We report the first observation of second harmonic generation (SHG) from halide double perovskite single crystals. The SHG efficiency of these materials with centrosymmetric crystalline structures is strongly dependent on the measurement temperature, increasing by up to 3 orders of magnitude at low temperatures under light illumination. The enhancement is attributed to the build-up of a light-induced electric field within the near-surface region.
