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Chinese physics B 2024年第5期33卷 117-123页

作者：吴思远朱天念涂思佳肖睿娟袁洁吴泉生李泓翁红明 Institute of physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China College of Materials Science and Optoelectronic Technology University of Chinese Academy of SciencesBeijing 100049China condensed matter physics Data Center of Chinese Academy of Sciences Beijing 100190China

The exponential growth of literature is constraining researchers’access to comprehensive information in related *** natural language processing(NLP)may offer an effective solution to literature classification,it remains hindered by the lack of labelled *** this article,we introduce a novel method for generating literature classification models through semi-supervised learning,which can generate labelled dataset iteratively with limited human *** apply this method to train NLP models for classifying literatures related to several research directions,i.e.,battery,superconductor,topological material,and artificial intelligence(AI)in materials *** trained NLP‘battery’model applied on a larger dataset different from the training and testing dataset can achieve F1 score of 0.738,which indicates the accuracy and reliability of this ***,our approach demonstrates that even with insufficient data,the not-well-trained model in the first few cycles can identify the relationships among different research fields and facilitate the discovery and understanding of interdisciplinary directions.

关键词： natural language processing text mining materials science

High-Quality and Wafer-Scale Cubic Silicon Carbide Single Crystals

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Energy & Environmental Materials 2024年第4期7卷 442-449页

作者： Guobin Wang Da Sheng Yunfan Yang Hui Li Congcong Chai Zhenkai Xie Wenjun Wang Jiangang Guo Xiaolong Chen Beijing National laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Cubic silicon carbide (3C-SiC) has superior mobility and thermal conduction over that of widely applied hexagonal ***,much lower concentration of interfacial traps between insulating oxide gate and3C-SiC helps fabrica... 详细信息

关键词： cubic SiC high-temperature solution growth high-temperature surface tension solid–liquid interfacial energy wide band gap semiconductor

Magnetism of NaYbS2: From finite temperatures to ground state

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Science China(physics,Mechanics & Astronomy) 2024年第10期Mechanics & Astronomy) .卷 96-108页

作者： Weizhen Zhuo Zheng Zhang Mingtai Xie Anmin Zhang Jianting Ji Feng Jin Qingming Zhang School of Physical Science and Technology Lanzhou University Beijing National laboratory for condensed matter physics Institute of PhysicsChinese Academy of Sciences

Rare-earth chalcogenide compounds ARECh2（A=alkali or monovalent metal,RE=rare earth,Ch=O,S,Se,Te） are a large family of quantum spin liquid（QSL） candidate ***2is a representative member of the *** key issues on NaYbS2,particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state,remain to be *** this paper,we conducted an in-depth and comprehensive study on the magnetism of NaYbS2from finite temperatures to the ground ***,we successfully detected three crystalline electric field（CEF） excitation energy levels using low-temperature Raman scattering *** them with the CEF theory and magnetization data,we worked out the CEF parameters,CEF energy levels,and CEF *** further determined a characteristic temperature of ～40 K,above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main *** characteristic temperature has been confirmed by the temperature-dependent electron spin resonance（ESR） ***-temperature ESR experiments on the dilute magnetic doped crystal of NaYb0.1Lu0.9S2further helped us to determine the accurate ***,we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat ***,the above studies allow us to explore the ground state magnetism of NaYbS2by using the density matrix renormalization *** combined numerical calculations and experimental results to demonstrate that the ground state of NaYbS2is a Dirac-like QSL.

关键词： anisotropic spin Hamiltonian quantum spin liquid rare-earth chalcogenide

Observation of parabolic electron bands on superconductor LaRu2As2

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Chinese physics B 2024年第7期33卷 70-75页

作者：周兴泰李更潘禄禄陈子超李萌时延昊杨海涛高鸿钧 Beijing National Center for condensed matter physics and Institute of physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Hefei National laboratory

Ru-based superconductor LaRu2As2has been discovered exhibiting the highest critical temperature of ～ 7.8 K among iron-free transition metal pnictides with the ThCr2Si2-type crystal structure. However, microscopic research on this novel superconducting material is still lacking. Here, we utilize scanning tunneling microscopy/spectroscopy to uncover the superconductivity and surface structure of LaRu2As2. Two distinct terminating surfaces are identified on the cleaved crystals, namely, the As surface and the La surface. Atomic missing line defects are observed on the La surface. Both surfaces exhibit a superconducting gap of ～ 1.0 me V. By employing quasiparticle interference techniques, we observe standing wave patterns near the line defects on the La atomic plane. These patterns are attributed to quasiparticle scattering from two electron type parabolic bands.

关键词： superconductivity line defect quasi-particle scattering electron band

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Unconventional phonon spectra and obstructed edge phonon modes

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Science China(physics,Mechanics & Astronomy) 2024年第4期67卷 114-118页

作者： Ruihan Zhang Haohao Sheng Junze Deng Zhong Fang Zhilong Yang Zhijun Wang Beijing National laboratory for condensed matter physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Based on the elementary band representations(EBR),many topologically trivial materials are classified as unconventional ones(obstructed atomic limit),where the EBR decomposition for a set of electronic states is not consistent with atomic valenceelectron band *** the work,we identify that the unconventional nature can also exist in phonon spectra,where the EBR decomposition for a set of well-separated phonon modes is not consistent with atomic vibration band representations(ABR).The unconventionality has two types:typeⅠis on an empty site;and typeⅡis on an atom site with non-atomic vibration *** unconventionality is described by the nonzero real-space invariant at the *** detailed calculations show that the black phosphorus(BP)has the typeⅠunconventional phonon spectrum,while 1H-Mo Se_(2)has the typeⅡone,although their electronic structures are also ***,the obstructed phonon modes are obtained for two types of unconventional phonon spectra.

关键词： unconventional phonon spectra obstructed edge phonon mode typeⅠ&typeⅡunconventionality

Saturable absorption and visible pulse modulation of few-layer topological nodal-line semimetal HfGeTe

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Chinese Optics Letters 2024年第3期22卷 89-94页

作者：赵启明张首焱王树贤王刚于浩海张怀金 State Key laboratory of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan 250100China Beijing National laboratory for condensed matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Topological nodal-line semimetals attract growing research attention in the photonic and optoelectronic fields due to their unique topological energy-level bands and fascinating nonlinear optical ***,to the best of our knowledge,we first report the saturable absorption property of topological nodal-line semimetal HfGeTe and the related pulse modulation in passively Q-switched visible ***-layer HfGeTe demonstrates outstanding saturable absorption properties in the visible-light band,yielding the saturation intensities of 7.88,12.66,and 6.64μJ/cm^(2)at 515,640,and 720 nm,*** on an as-prepared few-layer HfGeTe optical switch and a Pr:LiYF_(4)gain medium,Q-switched visible lasers are also successfully achieved at 522,640,and 720 *** minimum pulse widths of the green,red,and deep-red pulsed lasers are150,125.5,and 420 ns,*** for the green and red pulsed laser,the obtained pulse width is smaller than those of the low-dimensional layered *** work sheds light on the application potential of topological nodal-line semimetals in the generation of visible pulsed lasers.

关键词： visible pulsed laser topological nodal-line semimetals saturable absorption Q-switching Pr doping

Finite Temperature Magnetism in the Triangular Lattice Antiferromagnet KErTe_(2)

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Chinese physics Letters 2024年第9期41卷 140-150页

作者： Weiwei Liu Zheng Zhang Dayu Yan Jianshu Li Zhitao Zhang Jianting Ji Feng Jin Youguo Shi Qingming Zhang Department of physics Renmin University of ChinaBeijing 100872China Beijing National laboratory for condensed matter physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China Anhui Province Key laboratory of condensed matter physics at Extreme Conditions High Magnetic Field LaboratoryChinese Academy of SciencesHefei 230031China School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China

After the discovery of the ARECh2(A=alkali or monovalent ions,RE=rare-earth,Ch=chalcogen)triangular lattice quantum spin liquid(QSL)family,a series of its oxide,sulfide,and selenide counterparts has been consistently reported and extensively *** KErTe_(2) represents the initial synthesized telluride member,preserving its triangular spin lattice,it was anticipated that the substantial tellurium ions could impart more pronounced magnetic attributes and electronic structures to this material *** study delves into the magnetism of KErTe_(2) at finite temperatures through magnetization and electron spin resonance(ESR)*** on the angular momentum J after spin-orbit coupling(SOC)and symmetry analysis,we obtain the magnetic effective Hamiltonian to describe the magnetism of Er^(3+)in R3m space *** the mean-field approximation to the Hamiltonian,we can simulate the magnetization and magnetic heat capacity of KErTe_(2) in paramagnetic state and determine the crystalline electric field(CEF)parameters and partial exchange *** relatively narrow energy gaps between the CEF ground state and excited states exert a significant influence on the *** example,small CEF excitations can result in a significant broadening of the ESR linewidth at 2 *** the fitted exchange interactions,although the values are small,given a large angular momentum J=15/2 after SOC,they still have a noticeable effect at finite ***,the heat capacity data under different magnetic fields along the𝑐axis direction also roughly match our calculated results,further validating the reliability of our analytical *** derived parameters serve as crucial tools for future investigations into the ground state magnetism of KErTe_(2).The findings presented herein lay a foundation for exploration of the intricate magnetism within the triangular-lattice delafossite family.

关键词： triangular Hamiltonian magnetization

Absence of BCS–BEC crossover in FeSe0.45Te0.55 superconductor

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Chinese physics B 2024年第7期33卷 89-96页

作者：贾俊杰谷亚东殷超辉束英杰陈逸雯史聚民张杏陈浩苗泰民任晓琳梁波朱文培蔡能张丰丰张申金杨峰王志敏彭钦军许祖彦毛寒青刘国东任治安赵林周兴江 National laboratory for Superconductivity Beijing National Laboratory for Condensed Matter PhysicsInstitute of Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Technical Institute of physics and Chemistry Chinese Academy of Sciences Songshan Lake Materials laboratory

In iron-based superconductor Fe（Se,Te）, a flat band-like feature near the Fermi level was observed around the Brillouin zone center in the superconducting state. It is under debate whether this is the evidence on the presence of the BCS–BEC[Bardeen–Cooper–Schrieffer（BCS）, Bose–Einstein condensation（BEC）] crossover in the superconductor. High-resolution laser-based angle-resolved photoemission measurements are carried out on high quality single crystals of FeSe0.45Te0.55superconductor to address the issue. By employing different polarization geometries, we have resolved and isolated the dyz band and the topological surface band, making it possible to study their superconducting behaviors separately. The dyz band alone does not form a flat band-like feature in the superconducting state and the measured dispersion can be well described by the BCS picture. We find that the flat band-like feature is formed from the combination of the dyz band and the topological surface state band in the superconducting state. These results reveal the origin of the flat band-like feature and rule out the presence of BCS-BEC crossover in Fe（Se,Te） superconductor.

关键词： FeSe_(0.45)Te_(0.55) ARPES electronic structure superconducting gap BCS-BEC crossover

Preparing highly entangled states of nanodiamond rotation and NV center spin

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Chinese physics B 2024年第2期33卷 144-151页

作者：李文亮周端陆 Institute of physics Beijing National Laboratory for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

A nanodiamond with an embedded nitrogen-vacancy(NV)center is one of the experimental systems that can be coherently manipulated within current *** between NV center electron spin and mechanical rotation of the nanodiamond plays a fundamental role in building a quantum network connecting these microscopic and mesoscopic degrees of *** we present a protocol to asymptotically prepare a highly entangled state of the total quantum angular momentum and electron spin by adiabatically boosting the external magnetic field.

关键词： nanodiamond NV center entanglement

Quantum synchronization with correlated baths

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Chinese physics B 2024年第2期33卷 152-157页

作者：李磊王春辉尹洪浩王如泉刘伍明 School of Physical Science and Technology Inner Mongolia UniversityHohhot 010021China Beijing National laboratory for condensed matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

We study quantum synchronization under the nonequilibrium *** consider a two-qubit XXZ chain coupled independently to their own reservoirs modeled by the collisional *** reservoir particles,initially prepared in a thermal state or a state with coherence,are correlated through a unitary transformation and afterward interact locally with the two quantum *** study the quantum effect of reservoir on synchronous dynamics of *** preparing different reservoir initial states or manipulating the reservoir particles coupling and the temperature gradient,we find that quantum entanglement of reservoir is the key to control quantum synchronization of system qubits.

关键词： quantum synchronization entanglement quantum coherence nonequilibrium reservoir