Article
Chemistry, Multidisciplinary
Weihao Li, Wenkai Zhu, Gaojie Zhang, Hao Wu, Shouguo Zhu, Runze Li, Enze Zhang, Xiaomin Zhang, Yongcheng Deng, Jing Zhang, Lixia Zhao, Haixin Chang, Kaiyou Wang
Summary: In this study, the perpendicular magnetization of the vdW ferromagnet Fe3GaTe2 was successfully switched at room temperature using spin-orbit torques with a relatively low current density. The high efficiency of this method, quantitatively determined by harmonic measurements, provides a significant basis for the development of vdW-ferromagnet-based spintronic applications.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Hongrui Zhang, Xiang Chen, Tianye Wang, Xiaoxi Huang, Xianzhe Chen, Yu-Tsun Shao, Fanhao Meng, Peter Meisenheimer, Alpha N'Diaye, Christoph Klewe, Padraic Shafer, Hao Pan, Yanli Jia, Michael F. Crommie, Lane W. Martin, Jie Yao, Ziqiang Qiu, David A. Muller, Robert J. Birgeneau, Ramamoorthy Ramesh
Summary: This study reports the experimental observation of spin-orbit torque magnetization self-switching at room temperature in a layered polar ferromagnetic metal, Fe2.5Co2.5GeTe2, providing a direct pathway towards applicable 2D spintronic devices.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Srija Alla, Vinod Kumar Joshi, Somashekara Bhat
Summary: Field-free magnetization switching via the interplay of spin orbit torque, exchange bias field, and voltage controlled magnetic anisotropy is crucial for the development of scalable, high speed, and energy-efficient spintronic memories.
JOURNAL OF APPLIED PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
Wei Tang, Haoliang Liu, Zhe Li, Anlian Pan, Yu-Jia Zeng
Summary: Spin-orbit torque (SOT) plays a crucial role in the electrical manipulation of magnetization in spintronic devices, with van der Waals-layered materials showing promising properties for efficient SOT applications. By converting charge current into spin current, these materials can effectively control magnetization.
Article
Materials Science, Multidisciplinary
Franziska Martin, Kyujoon Lee, Maurice Schmitt, Anna Liedtke, Aga Shahee, Haakon Thomt Simensen, Tanja Scholz, Tom G. Saunderson, Dongwook Go, Martin Gradhand, Yuriy Mokrousov, Thibaud Denneulin, Andras Kovacs, Bettina Lotsch, Arne Brataas, Mathias Klaeui
Summary: We investigate the current-induced magnetisation manipulation in two-dimensional Fe3GeTe2 material and find that its crystalline structure allows for the presence of both interfacial and bulk spin-orbit torques, enabling efficient magnetisation switching without the need for complex multilayer engineering.
MATERIALS RESEARCH LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Qidong Xie, Weinan Lin, Jinghua Liang, Hengan Zhou, Moaz Waqar, Ming Lin, Siew Lang Teo, Hao Chen, Xiufang Lu, Xinyu Shu, Liang Liu, Shaohai Chen, Chenghang Zhou, Jianwei Chai, Ping Yang, Kian Ping Loh, John Wang, Wanjun Jiang, Aurelien Manchon, Hongxin Yang, Jingsheng Chen
Summary: Van der Waals materials have attracted attention in spintronics due to their unique physical properties. This study reports the observation of current-induced spin-orbit torque (SOT) in the h-BN/SrRuO3 bilayer structure, where the vdW material is an insulator with negligible SOC. The strong SOT is capable of inducing perpendicular magnetization switching in SrRuO3, and calculations suggest a giant Rashba effect at the interface between vdW material and SrRuO3 thin film.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Kaixuan Zhang, Youjin Lee, Matthew J. Coak, Junghyun Kim, Suhan Son, Inho Hwang, Dong-Su Ko, Youngtek Oh, Insu Jeon, Dohun Kim, Changgan Zeng, Hyun-Woo Lee, Je-Geun Park
Summary: This research successfully demonstrates a multi-level spin memory using van-der-Waals (vdW) topological ferromagnet Fe3GeTe2, achieving nonvolatile and highly energy-efficient magnetization switching. The ability to control magnetic information with a tiny current and switch multiple states electrically shows great potential for enhancing information capacity density and reducing computing costs in spintronics.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yongcheng Deng, Weihao Li, Xiukai Lan, Enze Zhang, Runze Li, Yaxuan Shang, Shuai Liu, Baohe Li, Xionghua Liu, Houzhi Zheng, Kaiyou Wang
Summary: Field-free magnetization switching is achieved in spin orbit torque crossbar array devices. The mechanism of this switching is revealed through analyzing the current distribution and micromagnetic simulations. The demonstration of tristate switching and write protection is significant for the study and application of spin crossbar array devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Physics, Multidisciplinary
Tong-Xi Liu, Zhao-Hao Wang, Min Wang, Chao Wang, Bi Wu, Wei-Qiang Liu, Wei-Sheng Zhao
Summary: This study proposes a method for implementing both unipolar and bipolar switching of perpendicular magnetization within a single SOT device. The influence of key parameters on the switching mode is discussed. This proposal can be used to design novel reconfigurable logic circuits in the future.
Article
Physics, Multidisciplinary
Qian Chen, Weiming Lv, Shangkun Li, Wenxing Lv, Jialin Cai, Yonghui Zhu, Jiachen Wang, Rongxin Li, Baoshun Zhang, Zhongming Zeng
Summary: By inserting a monolayer MoTe2 with low crystal symmetry into Pt/Ni heterostructures, the spin orbit efficiency, out-of-plane magnetic anisotropy, and Gilbert damping of Ni have been enhanced due to orbital hybridization and increased spin scattering at the interface. Additionally, an out-of-plane damping-like torque is observed when the current is applied perpendicular to the mirror plane of the MoTe2 crystal, attributed to interfacial inversion symmetry breaking. This work offers a route for engineering SOT in Pt-based heterostructures and potential opportunities for van der Waals interfaces in spintronic devices.
Article
Physics, Multidisciplinary
Shutaro Karube, Takahiro Tanaka, Daichi Sugawara, Naohiro Kadoguchi, Makoto Kohda, Junsaku Nitta
Summary: The study investigates the generation of spin-splitter torque in collinear antiferromagnetic RuO2, revealing different spin current polarizations on various crystal planes. By utilizing this spin-splitter torque, field-free switching of ferromagnetic materials can be achieved, contributing to the development of antiferromagnetic spin-orbitronics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
H. Bai, L. Han, X. Y. Feng, Y. J. Zhou, R. X. Su, Q. Wang, L. Y. Liao, W. X. Zhu, X. Z. Chen, F. Pan, X. L. Fan, C. Song
Summary: This article provides experimental evidence of the spin splitting torque (SST) in collinear antiferromagnet RuO2 films, which combines the advantages of conventional spin transfer torque (STT) and spin-orbit torque (SOT) and enables controllable spin polarization. The findings not only expand the research field of spin torques but also propose the potential of RuO2 as a spin source.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Thow Min Cham, Saba Karimeddiny, Vishakha Gupta, Joseph A. Mittelstaedt, Daniel C. Ralph
Summary: Spin-orbit torques generated by exfoliated layers of low-symmetry semi-metal ZrTe3 are measured using the spin-torque ferromagnetic resonance (ST-FMR) technique. It was found that artifacts may affect the standard ST-FMR analysis within a certain thickness range. Accurate measurements can be achieved by using different methods to avoid this interference.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Review
Physics, Multidisciplinary
Chunli Tang, Laith Alahmed, Muntasir Mahdi, Yuzan Xiong, Jerad Inman, Nathan J. McLaughlin, Christoph Zollitsch, Tae Hee Kim, Chunhui Rita Du, Hidekazu Kurebayashi, Elton J. G. Santos, Wei Zhang, Peng Li, Wencan Jin
Summary: The discovery of atomic monolayer magnetic materials has led to intense research in the field of two-dimensional van der Waals (vdW) materials. This field has witnessed the emergence of a variety of 2D vdW magnetic compounds with unique properties, and has explored the applications of spintronics and optoelectronics. The control of spin dynamics is crucial for designing ultrafast spintronic devices, and ferromagnetic resonance (FMR) provides a direct method to study magnetic excitations and key parameters of magnetic properties.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Yu Zhang, Hongjun Xu, Ke Jia, Guibin Lan, Zhiheng Huang, Bin He, Congli He, Qiming Shao, Yizhan Wang, Mingkun Zhao, Tianyi Ma, Jing Dong, Chenyang Guo, Chen Cheng, Jiafeng Feng, Caihua Wan, Hongxiang Wei, Youguo Shi, Guangyu Zhang, Xiufeng Han, Guoqiang Yu
Summary: Spin-orbit torque (SOT) is a promising strategy to switch perpendicular magnetization without an external magnetic field, and using low-symmetry materials to generate SOT at room temperature is of great importance.
Article
Physics, Multidisciplinary
Seungju Shin, Hyun-Woo Lee
Summary: In this study, we use the tight-binding method and the Kubo formula to calculate the electric field-induced damping-like spin-orbit torque in a ferromagnetic metal/topological insulator bilayer. The results show that hybridized states at the interface between a ferromagnetic metal and a topological insulator are crucial for the large damping-like spin Hall conductivity. Our findings offer a possible explanation for the experimentally reported large damping-like spin-orbit torque in a ferromagnetic metal/topological insulator bilayer.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2022)
Article
Physics, Multidisciplinary
Seungyun Han, Hyun-Woo Lee, Kyoung-Whan Kim
Summary: In this theoretical study, it was demonstrated that orbital dynamics in time-reversal-symmetric centrosymmetric systems exhibit qualitatively different behaviors from spin dynamics due to the differing algebraic properties of orbital and spin angular momentum operators. The research sheds light on interesting orbital responses that do not have spin counterparts, such as oscillations in orbital angular momentum expectation values, even without breaking time-reversal or inversion symmetry. The work offers insight into experimental differentiation of orbital dynamics from spin dynamics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Hiroki Hayashi, Daegeun Jo, Dongwook Go, Tenghua Gao, Satoshi Haku, Yuriy Mokrousov, Hyun-Woo Lee, Kazuya Ando
Summary: Modern spintronics relies on the generation of spin currents through spin-orbit coupling. The spin-current generation has been believed to be triggered by current-induced orbital dynamics, which governs the angular momentum transfer from the lattice to the electrons in solids. The fundamental role of the orbital response in the angular momentum dynamics suggests the importance of the orbital counterpart of spin currents: orbital currents. Here, we demonstrate the generation of giant orbital currents and uncover fundamental features of the orbital response.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Seungyun Han, Hyun-Woo Lee, Kyoung-Whan Kim
Summary: In this work, the authors investigate the microscopic origins and strength of orbital textures, which are k-dependent orbital states. They derive the orbital texture Hamiltonians from microscopic tight-binding models and reveal two microscopic mechanisms for the hybridization of orbital states. By considering the orbital hybridization, they not only reproduce the orbital Hamiltonian obtained by symmetry analysis but also discover previously unreported orbital textures. These orbital Hamiltonians are valuable for analyzing orbital physics and designing materials for spin-orbitronic applications.
CURRENT APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Dongwook Go, Daegeun Jo, Kyoung-Whan Kim, Soogil Lee, Min-Gu Kang, Byong-Guk Park, Stefan Bluegel, Hyun-Woo Lee, Yuriy Mokrousov
Summary: Contrary to the common assumption, the orbital response in ferromagnets can exhibit remarkable long-ranged behavior, even in the presence of strong crystal field potential and orbital quenching. By studying a bilayer structure composed of a nonmagnet and a ferromagnet, it is found that induced orbital angular momentum can extend far beyond the spin dephasing length, even when an external electric field is applied only on the nonmagnet. This behavior is attributed to nearly degenerate orbital characters imposed by crystal symmetry, which form hotspots for the intrinsic orbital response. The findings suggest the potential use of long-range orbital response in orbitronic device applications.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Mijin Lim, Byeonghyeon Choi, Minjae Ghim, Je-Geun Park, Hyun-Woo Lee
Summary: In this study, the effect of a uniaxial tensile strain on the nodal line and the intrinsic anomalous Hall effect (AHE) in Fe3GeTe2 (FGT) was investigated using first-principles calculations and symmetry analysis. The results showed that the nodal line is robust to in-plane strain, and the intrinsic AHE remains robust even with artificial adjustment of atomic positions to break the crystalline symmetries of FGT. The presence of inversion symmetry or twofold screw symmetry maintains the degeneracy of the nodal line.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Multidisciplinary Sciences
Young-Gwan Choi, Daegeun Jo, Kyung-Hun Ko, Dongwook Go, Kyung-Han Kim, Hee Gyum Park, Changyoung Kim, Byoung-Chul Min, Gyung-Min Choi, Hyun-Woo Lee
Summary: The orbital Hall effect refers to the generation of transverse electron angular momentum flow in an external electric field. Contrary to common belief, theoretical studies suggest that the orbital Hall effect can be strong in transition metals and is an important factor in the spin Hall effect. Despite growing circumstantial evidence, direct detection of the orbital Hall effect remains challenging.
Article
Multidisciplinary Sciences
Kyuhwe Kang, Hiroki Omura, Daniel Yesudas, OukJae Lee, Kyung-Jin Lee, Hyun-Woo Lee, Tomoyasu Taniyama, Gyung-Min Choi
Summary: In this study, the spin current in a FeRh/Cu heterostructure during the ultrafast magnetization process is directly measured, revealing a significant correlation between the spin current and the magnetization dynamics. This suggests an angular momentum transfer mechanism from electrons to magnons, involving spatial transport and dissipation of angular momentum. This finding contributes to a better understanding of laser-induced ultrafast magnetization processes.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Jongjun M. Lee, Myung-Joong Hwang, Hyun-Woo Lee
Summary: The study investigates the possibility of combining cavity magnonics and topological insulators by exploring hybrid cavity systems incorporating a ferromagnet and a topological insulator. The researchers find that the topological surface state efficiently mediates the coupling between the spin of the ferromagnet and the electric field of the cavity, which is different from the conventional magnetic dipole coupling. They refer to this coupling as topological magnon-photon interaction and show that it is significantly stronger than the conventional magnon-photon coupling. The proposed device has the potential to scale down and control the cavity system using electronics.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Min Ju Park, Suik Cheon, Hyun-Woo Lee
Summary: Recent studies suggest that nonlinear transport properties in Weyl semimetals could be a measurable consequence of chiral anomaly. However, this work presents a semiclassical Boltzmann analysis that shows the nondivergence of the chiral charge pumping even at zero temperature. The study also demonstrates the overestimation of nonlinear properties in Weyl semimetals and provides the validity condition for the conventional approximation.
Article
Materials Science, Multidisciplinary
Mohsen Sabbaghi, Tobias Stauber, Hyun-Woo Lee, J. Sebastian Gomez-Diaz, George W. Hanson
Summary: This work investigates the in-plane optical phonon modes of current-carrying single-layer graphene and identifies the effects of DC current on the frequency shifts and the breaking of rotational symmetry.
Article
Materials Science, Multidisciplinary
Suik Cheon, Gil Young Cho, Ki-Seok Kim, Hyun-Woo Lee
Summary: This article discusses the possibility of realizing the chiral anomaly in noncentrosymmetric systems without pairs of Weyl points, where spin-orbit coupling induces nonzero Berry curvature flux through Fermi surfaces. This phenomenon affects both charge and spin transport properties, leading to the emergence of new physical effects.
Article
Materials Science, Multidisciplinary
Hojun Lee, Byeonghyeon Choi, Hyun-Woo Lee
Summary: The orientation dependence of the intrinsic orbital Hall effect (OHE) and spin Hall effect (SHE) in hexagonal close-packed (hcp) structure materials was investigated, revealing three symmetry-wise independent orientations in the hcp structure. The orbital Hall conductivity (OHC) of Sc and Zr was found to have significant orientation dependence, which could be utilized to experimentally probe the OHE.
Article
Materials Science, Multidisciplinary
Nam-Hui Kim, Qurat-ul-ain, Joonwoo Kim, Eunchong Baek, June-Seo Kim, Hyeon-Jong Park, Hiroshi Kohno, Kyung-Jin Lee, Sonny H. Rhim, Hyun-Woo Lee, Chun-Yeol You
Summary: The interfacial perpendicular magnetic anisotropy (iPMA) and interfacial Dzyaloshinskii-Moriya interaction (iDMI) in ferromagnet/heavy metal bilayers exhibit similar Slater-Pauling-like dependence on the FM variation as the saturation magnetization (MS) does. This finding suggests that the density of states structure important for the Slater-Pauling dependence is crucial for iPMA and iDMI as well, providing a useful method to engineer chiral magnetic textures.
