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First-Principles Calculations of the quantum Size Effects on the Stability and Reactivity of Ultrathin Ru (0001) Films

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Chinese Physics Letters 2015年第6期32卷 131-135页

作者：武明义贾瑜孙强 international Laboratory for quantum Functional materials of Henan and School of Physics and EngineeringZhengzhou University

We carry out first-principles calculations of Ru（0001） films up to 30 monolayers （MLs） to study the quantum size effect （Q, SE） of Ru films for two cases： the freestanding Ru films and Ru films on Pt（111） substrates. Our studies show that the properties of these films （surface energy, work-function, charge density decay length in a vacuum and chemical reactivity） exhibit pronounced oscillatory behavior as a function of the film thickness, with an oscillation period of about four MLs for both cases due to the relationship of the match between the Fermi wave vector and the film thickness. Due to the localization of d-electron of Ru films, these quantum oscillations almost disappear when the thickness of the film is more than -20 ML for the free standing Ru films, while for the Ru films on Pt substrates the oscillations disappear quickly when the thickness of the film is beyond -13 ML. Our results reveal that the stability and reactivity of the Ru films could be tailored through Q, SE and the Ru bilayer grown on Pt substrates observed in the experiment is also related to the effect.

关键词： First-Principles Calculations of the quantum Size Effects on the Stability and Reactivity of Ultrathin Ru Pt Films

Research hotspot and trend of plant water use in karst: Based on a bibliometric analysis from 1984 to 2022

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China Geology 2025年第1期8卷 214-229页

作者： De-gen Zhu Jing Ning Hui Yang Jun-bing Pu Jian-hua Cao Meng-xia Zhou Mitja Prelovsek Natasa Ravbar Key Laboratory of Karst Dynamics MNR and Guangxi Institute of Karst GeologyChinese Academy of Geological SciencesGuilin 541000China international Research Center on Karst under the Auspices of UNESCO National Center for International Research on Karst Dynamic System and Global ChangeGuilin 541000China Pingguo Guangxi Karst EcosystemNational Observation and Research StationPingguo 531406China Chongqing Normal University Chongqing 400000China Research centre of the Slovenian Academy of Sciences and Art Karst Research InstituteTitov trg 26230 PostojnaSlovenia

Research on the ecohydrological processes of terrestrial plants is a frontier field comprising ecology,hydrology and global change research,yielding the key theoretical foundations of *** karst areas,due to its unique geological background,the karst landscape is strongly developed,with high bedrock exposure,high permeability,fragmented soils,shallow soils,and high spatial heterogeneity,resulting in very limited water storage for plant uptake and growth in rock fissures and shallow ***,water conditions are an important ecological factor influencing plant *** comprehensively understand the current progress and development trends in plant water use research focusing on karst areas,this paper uses the VOSviewer software to analyze the literature on plant water use in karst areas between 1984 and *** results showed that:(1)Research on plant water use in karst areas has developed rapidly worldwide,and the number of relevant studies in the literature have increased year by year,which together means that it is attracting more and more attention.(2)The investigation of plant water sources,geological background of karst areas,seasonal arid tropical climates,the relationship betweenδ13C values and plant water use efficiency,karst plant water use in karst savannas and subtropical areas,and ecosystems under climate change yields the knowledge base in this field.(3)Most studies in this area focus on the division of water sources of plants in karst areas,the methods of studying the water use sources of plants,and the water use strategies and efficiency of plants.(4)Future research will focus on how plant water use in karst areas is influenced by Earth’s critical zones,climate change,and ecohydrological *** studies will provide a key scientific basis for guiding ecological restoration and promoting sustainable development in karst areas.

关键词： Terrestrial plants Plant water use Karst area Climate change Ecohydrology Bibliometrics Ecological restoration Sustainable development Environmental restoration engineering Web of Science

Progress in bulk MgCu_2-type rare-earth iron magnetostrictive compounds

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Chinese Physics B 2013年第7期22卷 11-27页

作者：任卫军张志东 Shenyang National Laboratory for materials Science and international centre for materials Physics Institute of Metal ResearchChinese Academy of Sciences

Studies of bulk MgCu2-type rare-earth iron compounds with Laves phase are reviewed. The relationship between magnetostriction and structural distortion and the consequent crystallographic method for measuring magnetostriction are introduced at first. Then we review recent progress in understanding bulk magnetostrictive Laves phase materials, especially the magnetostriction and the minimization of the anisotropy of the light rare-earth Pr- and Sm-based compounds. Finally, a summary and outlook for this kind of compounds are presented.

关键词： magnetostriction anisotropy Laves compound

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磁性外尔半金属中的平面霍尔平台（英文）

Science Bulletin 2025年第2期 187-192页

作者：黎磊崔朝喜张闰午余智明姚裕贵 centre for quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE)School of PhysicsBeijing Institute of Technology Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology international Center for quantum materials Beijing Institute of Technology

Despite the rapid progress in the study of planar Hall effect(PHE) in recent years, all the previous works only showed that the PHE is connected to local geometric quantities, such as Berry curvature. Here, for the first time, we point out that the PHE in magnetic Weyl semimetals is directly related to a global quantity, namely, the Chern number of the Weyl point. This leads to a remarkable consequence that the PHE observation predicted here is robust against many system details, including the Fermi energy. The main difference between non-magnetic and magnetic Weyl points is that the latter breaks time-reversal symmetry T, thus generally possessing an energy tilt. Via semiclassical Boltzmann theory, we investigate the PHE in generic magnetic Weyl models with energy tilt and arbitrary Chern number. We find that by aligning the magnetic and electric fields in the same direction, the trace of the PHE conductivity contributed by Berry curvature and orbital moment is proportional to the Chern number and the energy tilt of the Weyl points, resulting in a previously undiscovered quantized PHE plateau by varying the Fermi *** further confirm the existence of PHE plateaus in a more realistic lattice model without T *** proposing a new quantized physical quantity, our work not only provides a new tool for extracting the topological character of the Weyl points but also suggests that the interplay between topology and magnetism can give rise to intriguing physics.

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Exchange couplings in magnetic films

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Chinese Physics B 2013年第2期22卷 1-22页

作者：刘伟刘雄华崔伟斌龚文杰张志东 Shenyang National Laboratory for materials Science and international centre for materials Physics Institute of Metal Research Chinese Academy of Sciences

Recent advances in the study of exchange couplings in magnetic films are *** provide a comprehensive understanding of exchange coupling,we have designed different bilayers,trilayers and multilayers,such as anisotropic hard/soft-magnetic multilayer films,ferromagnetic/antiferromagnetic/ferromagnetic trilayers,[Pt/Co]/NiFe/NiO heterostructures,Co/NiO and Co/NiO/Fe trilayers on an anodic aluminum oxide（AAO） *** exchange-coupling interaction between soft-and hard-magnetic phases,interlayer and interfacial exchange couplings and magnetic and magnetotransport properties in these magnetic films have been investigated in detail by adjusting the magnetic anisotropy of ferromagnetic layers and by changing the thickness of the spacer layer,ferromagnetic layer,and antiferromagnetic *** particular physical phenomena have been observed and explained.

关键词： exchange interaction magnetic anisotropy magnetic properties of interfaces(multilayers superlattices heterostructures)

Enhanced Cryogenic Magnetocaloric Effect Induced by Small Size GdNi_5 Nanoparticles

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Journal of materials Science & Technology 2014年第10期30卷 973-978页

作者： Jun Li Song Ma Han Wang Wenjie Gong Jingjing Jiang Shaojie Li Yong Wang Dianyu Geng Zhidong Zhang Shenyang National Laboratory for materials Science Institute of Metal Researchand International Centre for Materials PhysicsChinese Academy of Sciences

GdNi5 nanoparticles and GdNis/Gd2O3 nanocapsules （with GdNi5 core and Gd2O3 shell） were prepared by arcdischarge technique under different hydrogen partial pressure. The GdNi5 nanoparticles show irregular spherical shape and have a size distribution of 10-50 nm with an average diameter of 15 nm. In comparison, the GdNi5/Gd2O3 nanocapsules present spherical morphology and show a size distribution of 10-100 nm with an average diameter of 60 nm. Under a magnetic field change of 50 kOe, the maximum magnetic entropy change of GdNi5 nanoparticles is 13.5 J/（kg K） at 5 K, while the corresponding value of the GdNis/Gd2O3 nanocapsuels is only 5.7 J/（kg K） at 31 K. The origin of the large magnetic entropy change of GdNi5 nanoparticles is ascribed to its high atomic moments and small anisotropy energy barrier induced by its small particle size.

关键词： Nanoparticle Superparamagnetic property Cryogenic refrigeration Magnetocaloric effect Nanocapsule

Revealing the frequency-dependent oscillations in the nonlinear terahertz response induced by the Josephson current

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National Science Review 2023年第11期10卷 110-117页

作者： Sijie Zhang Zhiyuan Sun Qiaomei Liu Zixiao Wang Qiong Wu Li Yue Shuxiang Xu Tianchen Hu Rongsheng Li Xinyu Zhou Jiayu Yuan Genda Gu Tao Dong Nanlin Wang international Center for quantum materials School of PhysicsPeking University State Key Laboratory of Low-Dimensional quantum Physics and Department of Physics Tsinghua University Condensed Matter Physics and materials Science Department Brookhaven National Lab Beijing Academy of quantum Information Sciences

Nonlinear responses of superconductors to intense terahertz radiation has been an active research *** terahertz pump-terahertz probe spectroscopy, we investigate the c-axis nonlinear optical response of a high-temperature superconducting cuprate. After excitation by a single-cycle terahertz pump pulse, the reflectivity of the probe pulse oscillates as the pump-probe delay is varied. Interestingly, the oscillatory central frequency scales linearly with the probe frequency, a fact widely overlooked in pump-probe experiments. By theoretically solving the nonlinear optical reflection problem on the interface, we show that our observation is well explained by the Josephson-type third-order nonlinear electrodynamics, together with the emission coefficient from inside the material into free space. The latter results in a strong enhancement of the emitted signal whose physical frequency is around the Josephson plasma edge. Our result offers a benchmark for and new insights into strong-field terahertz spectroscopy of related quantum materials.

关键词： high-temperature superconducting cuprates nonlinear optics time-domain tarahertz

The detection,extraction and parameter estimation of extreme-mass-ratio inspirals with deep learning

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 82-92页

作者： Qianyun Yun Wen-Biao Han Yi-Yang Guo He Wang Minghui Du Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310124China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Taiji Laboratory for Gravitational Wave Universe(Beijing/Hangzhou) University of Chinese Academy of SciencesBeijing 100049China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu ProvinceKey Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China international centre for Theoretical Physics Asia-Pacific(ICTP-AP) University of Chinese Academy of Sciences(UCAS)Beijing 100049China Center for Gravitational Wave Experiment National Microgravity LaboratoryInstitute of MechanicsChinese Academy of SciencesBeijing 100190China

One of the primary goals of space-borne gravitational wave detectors is to detect and analyze extreme-mass-ratio inspirals(EM-RIs).This task is particularly challenging because EMRI signals are complex,lengthy,and *** this work,we introduce a 2-layer convolutional neural network(CNN)approach to detect EMRI signals for space-borne detectors,achieving a true positive rate(TPR)of 96.9%at a 1%false positive rate(FPR)for signal-to-noise ratio(SNR)from 50 to ***,the key intrinsic parameters of EMRIs such as the mass,spin of the supermassive black hole(SMBH)and the initial eccentricity of the orbit can also be inferred directly by employing a neural *** mass and spin of the SMBH can be determined at 99%and 92%*** will greatly reduce the parameter spaces and computing cost for the following Bayesian parameter *** model also has a low dependency on the accuracy of the waveform *** study underscores the potential of deep learning methods in EMRI data analysis,enabling the rapid detection of EMRI signals and efficient parameter estimation.

关键词： gravitational wave EMRIs deep-learing

Experimental Realization of Degenerate Fermi Gases of ^(87)Sr Atoms with 10 or Two Spin Components

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Chinese Physics Letters 2019年第9期36卷 18-22页

作者： Wei Qi Ming-Cheng Liang Han Zhang Yu-Dong Wei Wen-Wei Wang Xu-Jie Wang Xibo Zhang international Center for quantum materials School of PhysicsPeking UniversityBeijing 100871 Collaborative Innovation Center of quantum Matter Beijing 100871 Beijing Academy of quantum Information Sciences Beijing 100193

We report the experimental realization of quantum degenerate Fermi gases of87Sr atoms under controlled 10-and dual-nuclear-spin *** on laser cooling and evaporative cooling,we achieve an ultracold Fermi gas of 10^(5)atoms equally distributed over 10 spin states,with a temperature of T/T_(F)=*** further prepare a dual-spin gas by optically pumping atoms to the m_(F)=9/2 and m_(F)=7/2 states and observe a slightly lower T/T_(F)than that for a 10-spin gas under the same trapping condition,showing efficient evaporative cooling under a decreasing number N of spin states(N≥2)despite the increasing importance of Pauli *** that rethermalization becomes less efficient with N approaching unity,we evaporatively cool an almost polarized gas to 130 *** simple and efficient preparation of ultracold Fermi gases of^(87)Sr with tunable spin configurations provides a first step towards engineering topological quantum systems.

关键词： Atoms