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Erratum to"Topological spin textures in electronic non-Hermitian systems"[Sci Bull 2024;69:325-333]

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Science Bulletin 2024年第9期69卷 1353-1354页

作者： Xiao-Xiao Zhang Naoto Nagaosa RIKEN Center for Emergent Matter Science(cems) WakoSaitama 351-0198 Japan epartment of Applied Physics University of TokyoTokyo 113-8656Japan

The publisher regrets to note that a production error has occurred in the placement of the two entire graphics of Fig.1 and Fig.2.The two entire graphics are wrongly exchanged in their position although the figure cap... 详细信息

关键词： graphics figure wrong

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电子非厄米系统中的拓扑自旋图样（英文）

Science Bulletin 2024年第3期 325-333页

作者：张骁骁 Naoto Nagaosa RIKEN Center for Emergent Matter Science (cems) Department of Applied Physics University of Tokyo

Non-Hermitian systems have been discussed mostly in the context of open systems and nonequilibrium.Recent experimental progress is much from optical, cold-atomic, and classical platforms due to the vast tunability and clear identification of observables. However, their counterpart in solid-state electronic systems in equilibrium remains unmasked although highly desired, where a variety of materials are available, calculations are solidly founded, and accurate spectroscopic techniques can be applied. We demonstrate that, in the surface state of a topological insulator with spin-dependent relaxation due to magnetic impurities, highly nontrivial topological soliton spin textures appear in momentum space.Such spin-channel phenomena are delicately related to the type of non-Hermiticity and correctly reveal the most robust non-Hermitian features detectable spectroscopically. Moreover, the distinct topological soliton objects can be deformed to each other, mediated by topological transitions driven by tuning across a critical direction of doped magnetism. These results not only open a solid-state avenue to exotic spin patterns via spin-and angle-resolved photoemission spectroscopy, but also inspire non-Hermitian dissipation engineering of spins in solids.

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Tunable quantum anomalous Hall effects in ferromagnetic van der Waals heterostructures

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National Science Review 2024年第3期11卷 100-107页

作者： Feng Xue Yusheng Hou Zhe Wang Zhiming Xu Ke He Ruqian Wu Yong Xu Wenhui Duan Beijing Academy of Quantum Information Sciences State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices Center for Neutron Science and Technology School of Physics Sun Yat-sen University State Key Laboratory of Surface Physics Key Laboratory of Computational Physical Sciences and Department of PhysicsFudan University Frontier Science Center for Quantum Information Department of Physics and Astronomy University of California-Irvine Tencent Quantum Laboratory Tencent Technology(Shenzhen)Co.Ltd RIKEN Center for Emergent Matter Science(cems) Institute for Advanced Study Tsinghua University

The quantum anomalous Hall effect（QAHE） has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers C = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers C = ±3 can be realized in a single material candidate, which is composed of van der Waals（vdW）coupled Bi and MnBi2Te4monolayers. The switching between different phases of QAHE can be controlled in multiple ways, such as applying strain or（weak） magnetic field or twisting the vdW materials. The prediction of an experimentally available material system hosting robust, highly tunable QAHE will stimulate great research interest in the field. Our work opens a new avenue for the realization of tunable QAHE and provides a practical material platform for the development of topological electronics.

关键词： quantum anomalous Hall effect topological quantum phase transition van der Waals heterostructures tunable Chern number high Chern number

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二维范德华磁体的拓扑自旋结构的研究进展

Science Bulletin 2024年第11期69卷 1612-1616页

作者：许洪军刘艺舟 Giovanni Finocchio Kang LWang 于国强 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsUniversity of Chinese Academy of SciencesChinese Academy of SciencesBeijing 100190China RIKEN Center for Emergent Matter Science(cems) Wako 351-0198Japan Department of Mathematical and Computer Sciences Physical Sciences and Earth SciencesUniversity of MessinaMessina 98166Italy Department of Electrical Engineering University of CaliforniaLos Angeles CA 90095USA

The importance of topological spin textures(TSTs), such as skyrmions, merons, hopfions, etc., is due to their static and dynamic properties [1]. They carry a topological number that characterizes the homotopy group Π... 详细信息

关键词：自旋结构 topological homotopy

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Direct observation of nodeless superconductivity and phonon modes in electron-doped copper oxide Sr1-XNdXCuO2

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National Science Review 2022年第4期9卷 76-83页

作者： Jia-Qi Fan Xue-Qing Yu Fang-Jun Cheng Heng Wang Ruifeng Wang Xiaobing Ma Xiao-Peng Hu Ding Zhang Xu-Cun Ma Qi-Kun Xue Can-Li Song State Key Laboratory of Low-Dimensional Quantum Physics Department of PhysicsTsinghua University Frontier Science Center for Quantum Information Beijing Academy of Quantum Information Sciences RIKEN Center for Emergent Matter Science (cems) Southern University of Science and Technology

The microscopic understanding of high-temperature superconductivity in cuprates has been hindered by the apparent complexity of crystal structures in these materials.We used scanning tunneling microscopy and spectroscopy to study the electron-doped copper oxide compound Sr1-xNdxCuO2,which has only bare cations separating the CuO2planes and thus the simplest infinite-layer structure of all cuprate superconductors.Tunneling conductance spectra of the major CuO2planes in the superconducting state reve aled direct evidence for a nodeless pairing gap,regardless of variation of its magnitude with the local doping of trivalent neodymium.Furthermore,three distinct bosonic modes are observed as multiple peak-dip-hump features outside the superconducting gaps and their respective energies depend little on the spatially varying gaps.As well as the bosonic modes,with energies identical to those of the external,bending and stretching phonons of copper oxides,our findings reveal the origin of the bosonic modes in lattice vibrations rather than spin excitations.

关键词： nodeless superconductivity phonon modes cuprate superconductors CuO2 plane

Null-free False Discovery Rate Control Using Decoy Permutations

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 235-253页

作者： Kun He Mengjie Li Yan Fu Fuzhou Gong Xiaoming Sun Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China cems NCMISRCSDSAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The traditional approaches to false discovery rate(FDR)control in multiple hypothesis testing are usually based on the null distribution of a test statistic.However,all types of null distributions,including the theoretical,permutation-based and empirical ones,have some inherent drawbacks.For example,the theoretical null might fail because of improper assumptions on the sample distribution.Here,we propose a null distributionfree approach to FDR control for multiple hypothesis testing in the case-control study.This approach,named target-decoy procedure,simply builds on the ordering of tests by some statistic or score,the null distribution of which is not required to be known.Competitive decoy tests are constructed from permutations of original samples and are used to estimate the false target discoveries.We prove that this approach controls the FDR when the score function is symmetric and the scores are independent between different tests.Simulation demonstrates that it is more stable and powerful than two popular traditional approaches,even in the existence of dependency.Evaluation is also made on two real datasets,including an arabidopsis genomics dataset and a COVID-19 proteomics dataset.

关键词： multiple testing false discovery rate null distribution-free p-value-free decoy permutations knockoff filter

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Vibration-assisted coherent excitation energy transfer in a detuned dimer

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Chinese Physics B 2017年第3期26卷 465-473页

作者：王信陈浩李晨宇李宏荣 School of Science Xi'an Jiaotong University cems RIKEN School of Science Xi'an Jiaotong University

The important role of high-energy intramolecular vibrational modes for excitation energy transfer in the detuned photosynthetic systems is studied. Based on a basic dimer model which consists of two two-level systems （pigments） coupled to high-energy vibrational modes, we find that the high-energy intramolecular vibrational modes can enhance the energy transfer with new coherent transfer channels being opened when the phonon energy matches the detuning between the two pigments. As a result, the energy can be effectively transferred into the acceptor. The effective Hamiltonian is obtained to reveal the strong coherent energy exchange among the donor, the acceptor, and the high-energy intramolecular. A semi-classical explanation of the phonon-assisted mechanism is also shown.

关键词： excitation energy transfer high-energy intramolecular vibrational motion dynamically resonantcoherent transfer

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Realizing quinary charge states of solitary defects in two-dimensional intermetallic semiconductor

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National Science Review 2022年第2期9卷 63-69页

作者： Jian Gou Bingyu Xia Xuguang Wang Peng Cheng Andrew Thye Shen Wee Wenhui Duan Yong Xu Kehui Wu Lan Chen Institute of Physics Chinese Academy of Sciences School of Physics University of Chinese Academy of Sciences Department of Physics National University of Singapore State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Institute for Advanced Study Tsinghua University Collaborative Innovation Center of Quantum Matter RIKEN Center for Emergent Matter Science (cems) Songshan Lake Materials Laboratory

Creating and manipulating multiple charge states of solitary defects in semiconductors is of essential importance for solitary defect electronics,but is fundamentally limited by Coulomb’s law.Achieving this objective is challenging,due to the conflicting requirements of the localization necessary for the sizable band gap and delocalization necessary for a low charging energy.Here,using scanning tunneling microscopy/spectroscopy experiments and first-principles calculations,we realized exotic quinary charge states of solitary defects in two-dimensional intermetallic semiconductor Sn2Bi.We also observed an ultralow defect charging energy that increases sublinearly with charge number rather than displaying the usual quadratic behavior.Our work suggests a promising route for constructing multiple defect-charge states by designing intermetallic semiconductors,and opens new opportunities for developing quantum devices with charge-based quantum states.

关键词： 2D materials intermetallic semiconductor tip-induced band bending solitary defect defect charging

Do bosons always condense?

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National Science Review 2021年第3期8卷 10-11页

作者： Yoshihiro Iwasa Quantum Phase Electronics Center (QPEC) and Department of Applied Physics The University of Tokyo RIKEN Center for Emergent Matter Science (cems)

We learn in elementary statistical mechanics that bosonic systems undergo a phase change even without interparticle interactions, called Bose-Einstein condensation (BEC). Indeed, almost all bosonic systems in the real world such as4He, cold atoms and photons, exhibit BEC, and even electrons, a representative fermion system, can show similar condensation and superconductivity through the Cooper pair formation.

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