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
Longxing Chi, Chandra Veer Singh, Jun Nogami
Summary: This study reports a Pb-induced surface reconstruction on Bi/Si(111) alpha phase, with the atomic structure determined using STM and DFT. Quantum well states (QWSs) and a significant Rashba band splitting are predicted, comparable to other semiconductor heterostructures and significantly higher than Pb/Si(111) QWSs.
Article
Chemistry, Physical
Jiajia Chen, Kai Wu, Wei Hu, Jinlong Yang
Summary: Research shows that 2D polar perovskites have large Rashba constants and strong electric field responses, making them suitable for use in spin FETs, enabling a short spin channel length of tens of nanometers to preserve spin coherence.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Physics, Multidisciplinary
Shuai Zhang, Fei Wang, Bin Cui, Chong Li, Yu Jia
Summary: The Rashba spin splitting of monovalent alkali metal adsorbed on Au/Si(111) surface is explained using first-principles calculations and analyses. It is found that Na adatom donates one electron to the pristine surface, leading to a large Rashba spin splitting in Na/Au/Si(111) system. Cs adsorbate, with larger intra-atomic spin-orbit coupling, not only plays the same role as Na adatom but also induces intrinsic spin-polarization, further enhancing the Rashba spin splitting on the Cs/Au/Si(111) surface. The proposed mechanism of intrinsic spin-polarization significantly enhancing the Rashba spin splitting is generally applicable and can be extended to alkali-earth metal epitaxial layers on Au/Si(111) surface.
Article
Chemistry, Multidisciplinary
Woo Seung Ham, Thi Huynh Ho, Yoichi Shiota, Tatsuya Iino, Fuyuki Ando, Tetsuya Ikebuchi, Yoshinori Kotani, Tetsuya Nakamura, Daisuke Kan, Yuichi Shimakawa, Takahiro Moriyma, Eunji Im, Nyun-Jong Lee, Kyoung-Whan Kim, Soon Cheol Hong, Sonny H. H. Rhim, Teruo Ono, Sanghoon Kim
Summary: Spin current, converted from charge current via spin Hall or Rashba effects, can transfer its angular momentum to local moments in a ferromagnetic layer. A high charge-to-spin conversion efficiency is required for developing future memory or logic devices, and here it is demonstrated in an artificial superlattice without centrosymmetry. The observed field-like torque efficiency in the [Pt/Co/W] superlattice with sub-nm scale thickness is about 0.6 when the W thickness becomes 0.6 nm, which is significantly higher than other metallic heterostructures.
Article
Chemistry, Physical
Shan-Shan Wang, Wencong Sun, Shuai Dong
Summary: In this study, a two-dimensional CX3 (X = Sb, Bi) monolayer was found to be a quantum spin Hall insulator with a large band gap, enabling the realization of the quantum spin Hall effect at room temperature. The topological properties of CX3 monolayer, including unique topologically entangled Rashba-splitting edge states, were preserved even with a h-BN substrate, providing potential applications in low-dissipation electronic devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Preeti Bhumla, Deepika Gill, Sajjan Sheoran, Saswata Bhattacharya
Summary: Spin-orbit coupling plays a key role in several intriguing quantum phenomena, including the Rashba-Dresselhaus effect. By studying the lead halide perovskite CsPbF3, researchers have discovered potential applications in spintronics, with tunable Rashba spin splitting and reversible spin textures observed. The findings suggest promising opportunities for perovskite-based spintronic devices.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Chiranjit Mondal, Chanchal K. Barman, Aftab Alam, Biswarup Pathak
Summary: The article presents a general symmetry-based mechanism to achieve intertwined giant Rashba splitting and topological nontrivial states simultaneously in a single crystalline system, supported by ab initio calculations. Significant values of Rashba parameters have been achieved in KSnSb0.625Bi0.375, surpassing those of widely studied topologically trivial Rashba semiconductor BiTeI.
Article
Materials Science, Multidisciplinary
Rongrong Xie, Panfeng Cao, Zheyuan Xu, Boyi Xu, Jinyue Fu, Xiaoli Zhu, Xianwei Fu, Sheng-Yi Xie, Ying Jiang, Anlian Pan
Summary: This study reports a significant out-of-plane spin polarization in the two-dimensional Dion-Jacobson (DJ) perovskite, which is the physical origin of the large Rashba spin splitting observed. The generation of this unconventional spin component indicates the significant influence of the in-plane asymmetric crystal field on the spin-orbit interactions. These results suggest that the studied system may serve as a type of spin source material to explore the attractive out-of-plane spin polarization.
Article
Chemistry, Multidisciplinary
Hongze Deng, Chenhui Zhang, Weizheng Liang, Xi-Xiang Zhang, Sheng-Nian Luo
Summary: In this study, the decay dynamics of hot carriers in a noncentrosymmetric semiconductor BiTeI with large spin-orbit splitting were investigated using time-resolved ultrafast optical spectroscopy. By tuning the pump photon energy, the decay behaviors of hot carriers in different energy bands were observed.
Article
Materials Science, Multidisciplinary
Lei Sun, Xikui Ma, Jian Liu, Mingwen Zhao
Summary: By using first-principles calculations and Floquet theory, we found that a significant anisotropic Rashba spin splitting can be induced in the valence and conduction bands of buckled honeycomb GaAs monolayer under specific laser irradiation conditions. This nonlinear effect, determined by the laser propagation direction, provides the possibility of controlling the anisotropy characteristics of Rashba effect and enables the generation of spin-polarized electrons for spintronic devices.
Article
Materials Science, Multidisciplinary
Ryo Noguchi, Kenta Kuroda, Mitsuaki Kawamura, Koichiro Yaji, Ayumi Harasawa, Takushi Iimori, Shik Shin, Fumio Komori, Taisuke Ozaki, Takeshi Kondo
Summary: The study utilized laser-SARPES technology to obtain new findings on spin- and angle-resolved photoemission spectroscopy of thin films, experimentally confirming the scalability of Rashba parameters and verifying it theoretically. By revealing the proportionality between Rashba parameters and charge density at the interface, as well as the spin-orbit coupling ratio, a new approach to tuning spin splitting in 2D heterostructure systems was provided.
Article
Materials Science, Multidisciplinary
M. J. Rendell, S. D. Liles, A. Srinivasan, O. Klochan, I Farrer, D. A. Ritchie, A. R. Hamilton
Summary: Magnetic focusing can be used to measure spin polarization and the strength of spin-orbit interaction in two-dimensional systems. By controlling the spatial separation of spins, the splitting of magnetic focusing peaks can be controlled.
Article
Materials Science, Multidisciplinary
L. L. Tao, Jiayu Li, Yuntian Liu, Xianjie Wang, Yu Sui, Bo Song, M. Ye. Zhuravlev, Qihang Liu
Summary: This article investigates the Rashba spin splitting phenomenon around non-time-reversal-invariant momenta and elucidates its microscopic origin. It is found that certain Bloch wave functions in specific non-invariant momentum regions can eliminate the first-order spin-orbit coupling effect, resulting in a tiny spin-orbit gap and helical spin texture. Furthermore, this quasi-symmetry-induced tiny gap can exhibit large Berry curvature, making it desirable for various topological applications. The study expands the concept of Rashba physics and paves the way for designing novel spin-splitting materials through the cooperation of symmetry and orbital engineering.
Article
Materials Science, Multidisciplinary
San-Dong Guo, Yu-Tong Zhu, Wen-Qi Mu, Xing-Qiu Chen
Summary: The study introduces a Janus monolayer SrAlGaSe4 with piezoelectric properties, showing a transition from normal insulator to topological insulator under biaxial strain, leading to the formation of a piezoelectric quantum spin Hall insulator. The research demonstrates that the nontrivial band topology of SrAlGaSe4 monolayer can be maintained within the strain range of 1.01 to 1.16, with coexisting piezoelectricity and topological orders.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Matteo Jugovac, Iulia Cojocariu, Jaime Sanchez-Barriga, Pierluigi Gargiani, Manuel Valvidares, Vitaliy Feyer, Stefan Bluegel, Gustav Bihlmayer, Paolo Perna
Summary: By europium doping, single spin-polarized bands can be generated in monolayer graphene supported by the Co(0001) surface. The doping is controlled by Eu positioning, allowing for the formation of a K over bar $\bar{\mathrm{K}}$-valley localized single spin-polarized low-dispersive parabolic band close to the Fermi energy when Eu is on top, and of a & pi;* flat band with single spin character when Eu is intercalated underneath graphene. In the latter case, Eu also induces a bandgap opening at the Dirac point while the Eu 4f states act as a spin filter, splitting the & pi; band into two spin-polarized branches. The generation of flat bands with single spin character, as revealed by the spin- and angle-resolved photoemission spectroscopy (ARPES) experiments, complemented by density functional theory (DFT) calculations, opens up new pathways toward the realization of spintronic devices exploiting such novel exotic electronic and magnetic states.
ADVANCED MATERIALS
(2023)
Article
Biochemistry & Molecular Biology
Iwona Lazar, Christian Rodenbuecher, Gustav Bihlmayer, Clive A. Randall, Janusz Koperski, Lutz Nielen, Krystian Roleder, Krzysztof Szot
Summary: Long-time electric field action causes chemical degradation in perovskite piezoelectric ceramics. A new method to accelerate this degradation is by exposing the ceramics to DC electric fields under vacuum. The study focuses on a high-quality commercial piezoelectric material based on PbZr1-xTixO3. The resistance changes during electrodegradation, resulting in electrically-induced deoxidation and transformation of the ceramic into a metallic-like material.
Article
Physics, Multidisciplinary
Tristan Heider, Gustav Bihlmayer, Jakub Schusser, Friedrich Reinert, Jan Minar, Stefan Bluegel, Claus M. Schneider, Lukasz Plucinski
Summary: We demonstrate a new type of geometry-induced spin filtering effect in photoemission in the important quantum material WTe2. The effect arises from its low symmetry, which also gives rise to its exotic transport properties. Through laser-driven spin-polarized angle-resolved photoemission Fermi surface mapping, we observe highly asymmetric spin textures of electrons emitted from the surface states of WTe2. The effect is a manifestation of time-reversal symmetry breaking in the photoemission process and can only be influenced by special experimental geometries.
PHYSICAL REVIEW LETTERS
(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
Chemistry, Multidisciplinary
Abdul-Vakhab Tcakaev, Bastian Rubrecht, Jorge. Facio, Volodymyr. B. Zabolotnyy, Laura. T. Corredor, Laura. C. Folkers, Ekaterina Kochetkova, Thiago R. F. Peixoto, Philipp Kagerer, Simon Heinze, Hendrik Bentmann, Robert. J. Green, Pierluigi Gargiani, Manuel Valvidares, Eugen Weschke, Maurits. W. Haverkort, Friedrich Reinert, Jeroen van den Brink, Bernd Buechner, Anja U. B. Wolter, Anna Isaeva, Vladimir Hinkov
Summary: The recent discovery of the quantum anomalous Hall effect (QAHE) in MnBi2Te4 and MnBi4Te7 indicates the potential of the (MnBi2Te4)(Bi2Te3)(n) family for further improvements in QAHE. The ferromagnetic (FM) ordered MnBi2Te4 septuple layers (SLs) in this family contribute to its promising nature. However, achieving QAHE in MnBi2Te4 and MnBi4Te7 is complicated due to the substantial antiferromagnetic (AFM) coupling between the SLs. By interlacing the SLs with an increasing number of Bi2Te3 quintuple layers (QLs), an FM state advantageous for QAHE can be stabilized. The mechanisms driving the FM state and the number of necessary QLs are not yet understood, and the surface magnetism remains unclear. This study demonstrates robust FM properties in MnBi6Te10 (n = 2) and establishes that its origin lies in the Mn/Bi intermixing phenomenon, thus consolidating its potential for QAHE at elevated temperatures.
Article
Nanoscience & Nanotechnology
Minh N. N. Bui, Stefan Rost, Manuel Auge, Lanqing Zhou, Christoph Friedrich, Stefan Bluegel, Silvan Kretschmer, Arkady V. V. Krasheninnikov, Kenji Watanabe, Takashi Taniguchi, Hans C. C. Hofsaess, Detlev Gruetzmacher, Beata E. E. Kardynal
Summary: This paper investigates the optical properties of an exfoliated MoSe(2) monolayer implanted with Cr+ ions accelerated to 25 eV. The photoluminescence of implanted MoSe2 exhibits an emission line from Cr-related defects, which is only observed under weak electron doping. Unlike band-to-band transitions, the emission introduced by Cr is characterized by nonzero activation energy, long lifetimes, and weak response to the magnetic field. By modeling the Cr-ion irradiation process using ab initio molecular dynamics simulations and electronic structure calculations, the authors provide insights into the atomic structure of the defects, suggesting recombination of electrons on acceptors with valence band holes as the most likely origin of the low-energy emission. The results demonstrate the potential of low-energy ion implantation as a doping tool to tailor the properties of two-dimensional materials.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Polina M. Sheverdyaeva, Conor Hogan, Gustav Bihlmayer, Jun Fujii, Ivana Vobornik, Matteo Jugovac, Asish K. Kundu, Sandra Gardonio, Zipporah Rini Benher, Giovanni Di Santo, Sara Gonzalez, Luca Petaccia, Carlo Carbone, Paolo Moras
Summary: Topological insulators are bulk insulators with metallic and fully spin-polarized surface states exhibiting Dirac-like band dispersion. By using spin-resolved photoemission spectroscopy, we show that the topological surface states of a topological insulator interfaced with an antimonene bilayer exhibit nearly full out-of-plane spin polarization within the substrate gap. This phenomenon is connected to a symmetry-protected band crossing of the spin-polarized surface states. The nearly full out-of-plane spin polarization of the topological surface states occurs along a continuous path in the energy-momentum space, and the spin polarization within the gap can be reversibly tuned from nearly full out-of-plane to nearly full in-plane by electron doping. These findings pave the way for advanced spintronics applications that exploit the giant out-of-plane spin polarization of topological surface states.
Article
Nanoscience & Nanotechnology
M. Merte, F. Freimuth, D. Go, T. Adamantopoulos, F. R. Lux, L. Plucinski, O. Gomonay, S. Bluegel, Y. Mokrousov
Summary: In this study, first principles methods are used to explore the physics of charge photocurrents, spin photocurrents, and the inverse Faraday effect in antiferromagnetic Mn2Au. The emergence of large spin photocurrents and the possibility of tracking the dynamics of staggered moments during switching are predicted. It is also suggested that even a small canting in Mn2Au can give rise to colossal chiral spin photocurrents. The unique blend of prominent photocurrents in Mn2Au makes it a unique platform for advanced optospintronics applications.
Article
Nanoscience & Nanotechnology
N. Biniskos, F. J. dos Santos, M. dos Santos Dias, S. Raymond, K. Schmalzl, P. Steffens, J. Persson, N. Marzari, S. Bluegel, S. Lounis, T. Brueckel
Summary: In this study, we investigate the spin-excitation spectrum of bulk Mn5Si3 using inelastic neutron scattering measurements and density functional theory calculations. We find that the spin dynamics of each phase in Mn5Si3 is robust against any combination of temperature and magnetic field. The high-energy spin dynamics exhibit distinctive characteristics of either spin waves or broad fluctuation patterns in different phases.
Article
Materials Science, Multidisciplinary
Raphael C. Vidal, Giovanni Marini, Lukas Lunczer, Simon Moser, Lena Fuerst, Julia Issing, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Charles Gould, Hartmut Buhmann, Wouter Beugeling, Giorgio Sangiovanni, Domenico Di Sante, Gianni Profeta, Laurens W. Molenkamp, Hendrik Bentmann, Friedrich Reinert
Summary: This study presents a joint experimental and theoretical investigation of the electronic structure in strained HgTe(001) films in the 3D topological-insulator regime, using angle-resolved photoelectron spectroscopy and density functional theory. The results demonstrate detailed agreement with theoretical predictions, including electronic band dispersions and orbital symmetries, surface and bulk contributions, and the importance of Hg 5d states in valence-band formation. The experiments directly image the paradigmatic band inversion in HgTe, revealing its nontrivial band topology.
Article
Chemistry, Multidisciplinary
Matteo Jugovac, Iulia Cojocariu, Jaime Sanchez-Barriga, Pierluigi Gargiani, Manuel Valvidares, Vitaliy Feyer, Stefan Blugel, Gustav Bihlmayer, Paolo Perna
Summary: By doping graphene with europium, single spin-polarized bands are generated, and the doping effect can be controlled by the positioning of europium. This doping enables the generation of flat bands with single spin character, providing new possibilities for the realization of spintronic devices.
ADVANCED MATERIALS
(2023)
Review
Physics, Applied
Emanuele Bosoni, Louis Beal, Marnik Bercx, Peter Blaha, Stefan Bluegel, Jens Broeder, Martin Callsen, Stefaan Cottenier, Augustin Degomme, Vladimir Dikan, Kristjan Eimre, Espen Flage-Larsen, Marco Fornari, Alberto Garcia, Luigi Genovese, Matteo Giantomassi, Sebastiaan P. Huber, Henning Janssen, Georg Kastlunger, Matthias Krack, Georg Kresse, Thomas D. Kuehne, Kurt Lejaeghere, Georg K. H. Madsen, Martijn Marsman, Nicola Marzari, Gregor Michalicek, Hossein Mirhosseini, Tiziano M. A. Mueller, Guido Petretto, Chris J. Pickard, Samuel Ponce, Gian-Marco Rignanese, Oleg Rubel, Thomas Ruh, Michael Sluydts, Danny E. P. Vanpoucke, Sudarshan Vijay, Michael Wolloch, Daniel Wortmann, Aliaksandr V. Yakutovich, Jusong Yu, Austin Zadoks, Bonan Zhu, Giovanni Pizzi
Summary: This article discusses recommendations for verifying the precision and transferability of density-functional theory computational approaches and codes, using an all-electron reference dataset. It emphasizes the importance of verification efforts and the need for standard computation protocols. The article also suggests further extensions in the verification efforts to cover more functionals and computational approaches.
NATURE REVIEWS PHYSICS
(2023)
