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Dimensionality-driven metal to Mott insulator transition in two-dimensional 1T-TaSe2

National Science Review 2024年第3期11卷 108-118页

作者： Ning Tian Zhe Huang Bo Gyu Jang Shuaifei Guo Ya-Jun Yan Jingjing Gao Yijun Yu Jinwoong Hwang Cenyao Tang Meixiao Wang Xuan Luo Yu Ping Sun Zhongkai Liu Dong-Lai Feng Xianhui Chen Sung-Kwan Mo Minjae Kim Young-Woo Son Dawei Shen Wei Ruan Yuanbo Zhang State Key Laboratory of Surface Physics New Cornerstone Science Laboratory and Department of PhysicsFudan University Shanghai Qi Zhi Institute Shanghai Research Center for Quantum Sciences Institute for Nanoelectronic Devices and Quantum Computing Fudan University Zhangjiang Fudan International Innovation Center Fudan University State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology(SIMIT)Chinese Academy of Sciences School of Physical Science and Technology ShanghaiTech University Korea Institute for Advanced Study School of Emerging Technology and Department of Physics University of Science and Technology of China Advanced Light Source Lawrence Berkeley National Laboratory ShanghaiTech Laboratory for Topological Physics Key Laboratory of Materials Physics Institute of Solid State Physics Hefei Institutes of Physical ScienceChinese Academy of Sciences High Magnetic Field Laboratory Hefei Institutes of Physical Science Chinese Academy of Sciences Collaborative Innovation Centre of Advanced Microstructures Nanjing University Department of Physics University of Science and Technology of China and Key Laboratory of Strongly Coupled Quantum Matter Physics Chinese Academy of Sciences National Synchrotron Radiation Laboratory University of Science and Technology of China

Two-dimensional materials represent a major frontier for research into exotic many-body quantum phenomena. In the extreme two-dimensional limit, electron-electron interaction often dominates over other electronic energy scales, leading to strongly correlated effects such as quantum spin liquid and unconventional *** dominance is conventionally attributed to the lack of electron screening in the third dimension. Here, we discover an intriguing metal to Mott insulator transition in 1T-TaSe2that defies conventional wisdom. Specifically, we find that dimensionality crossover, instead of reduced screening, drives the transition in atomically thin 1T-TaSe2. A dispersive band crossing the Fermi level is found to be responsible for the bulk metallicity in the material. Reducing the dimensionality,however, effectively quenches the kinetic energy of these initially itinerant electrons, and drives the material into a Mott insulating *** dimensionality-driven metal to Mott insulator transition resolves the long-standing dichotomy between metallic bulk and insulating surface of 1T-TaSe2. Our work further reveals a new pathway for modulating two-dimensional materials that enables exploring strongly correlated systems across uncharted parameter space.

关键词： two-dimensional materials 1T-TaSe2 dimensionality crossover metal to Mott insulator transition

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Strong correlation between ionic bonding strength and superconductivity in compressed hydrides

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Physical Review materials 2024年第8期8卷 084805-084805页

作者： Xing Li Zixuan Guo Yansun Yao Xiaohua Zhang Shicong Ding Guochun Yang State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province School of Science Department of Physics and Engineering Physics Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of

Understanding the superconductivity in relation to chemical bonding is essential for the development of superconductors. We propose that pressure-reduced ionic bonding strength is beneficial for improving superconductivity in hydrides (negative correlation between bonding strength and critical temperature). We model ionic hydrides using a prototypical ionic lattice (CsCl-type) with simple-valence metal Li/Rb and hydrogen and control the bonding strength via external pressure. First-principles calculations reveal that the ionic bonding strength in LiH increases with pressure while its critical temperature (Tc) simultaneously decreases. A higher Tc at lower pressures is attributed to stronger electron-phonon coupling (EPC) induced by weaker ionic bonds and significant EPC contributions from mid-frequency phonons. RbH's pressure dependences of bonding strength and Tc are the reverse of those of LiH, and the EPC primarily results from high-frequency phonons. The distinct interorbital electron transition mechanism and amounts of charge transfer are responsible for the opposite trend of changes in bonding strength and superconductivity in LiH and RbH. The proposed correlation is further validated by the other six ionic hydrides. Substantial Tc change (e.g., 126.2 K at 100 GPa and 5.7 K at 300 GPa in LiH) in response to bonding strength variation reveals a key factor for designing new superconductors.

关键词： Electronic structure First-principles calculations High-pressure studies Superconductivity

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Extremely fast vortex dynamics in Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrip

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Chinese Physics B 2023年第6期32卷 563-568页

作者：于奥博林成天张孝富尤立星 State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China CAS Center for Excellence in Superconducting Electronics(CENSE) Shanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Max Planck Institute for Solid State Research Heisenbergstrasse 1D-70569 StuttgartGermany

The maximum velocity of a mobile vortex in movement is generally limited by the phenomenon of flux-flow instability(FFI),which necessitates weak vortex pinning and fast heat removal from non-equilibrium *** here demonstrate exfoliations and nano-fabrications of Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips,which possess a rather weak pinning volume of vortices,relatively low resistivity,and large normal electron diffusion *** deduced vortex velocity in Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ) crystalline nanostrips can be up to 300 km/s near the superconducting transition temperature,well above the speed of *** observed vortex velocity is an order of magnitude faster than that of conventional superconducting systems,representing a perfect platform for exploration of ultra-fast vortex matter and a good candidate for fabrications of superconducting nanowire single photon detectors or superconducting THz modulator.

关键词： Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ)(Bi2223) vortices dynamics ultra thin single crystal nanowire

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Cyclic(Amino)(Aryl)Nitrenium Cations with Lewis Acidity Controlled by Remote Substituents

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Chinese Journal of Chemistry 2022年第3期40卷 311-316页

作者： Wenqing Wang Xin Zheng Leran Zhang Shunjie Li Yue Zhao Xinping Wang College of Chemistry and Material Science Key Laboratory of Functional Molecular SolidsMinistry of EducationAnhui Laboratory of Molecule-Based MaterialsAnhui Normal UniversityWuhuAnhui 241002China State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjingJiangsu 210023China College of Science Henan Agricultural UniversityZhengzhouHenan 450002China

N-Heterocyclic nitrogen Lewis acids are important in synthetic *** cyclic(amino)(aryl)nitrenium cations,cyc-1^(+)-cyc-3^(+),were synthesized by chemical oxidation of aryl azo compounds with different substituents,H and I,at the para positions of the phenyl *** excited triplet states of cyc-1^(+)-cyc-3^(+) abstract H-atoms step by step to generate radical intermediates cyc-1H^(*+-)cyc-3H^(*+)traced by EPR spectroscopy and products cyc-1H^(2+)-cyc-3H^(2+) characterized by single crystal X-ray *** Lewis acidity of species cyc-1^(+)-cyc-3^(+) are remote ***-2^(+)-cyc-3^(+) have much higher acidity than those previously reported congeners based on energies of *** electrophilicity enables them to form Lewis adducts with neutral Lewis base Me_(3)P,and to gain one-electron to produce neutral radicals cyc-1^(*)-cyc-3^(*).

关键词： Nitrenium cation Acidity Radicals Excited triplet state Electrophilicity

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Microwave heating as a universal method to transform confined molecules into armchair graphene nanoribbons

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Nano Research 2023年第7期16卷 10644-10651页

作者： Haoyuan Zhang Yingzhi Chen Kunpeng Tang Ziheng Lin Xuan Li Hongwei Zhang Yifan Zhang Chi Ho Wong Chi Wah Leung Chee Leung Mak Yuan Hu Weili Cui Kecheng Cao Lei Shi State Key Laboratory of Optoelectronic Materials and Technologies Nanotechnology Research CenterGuangdong Province Key Lab of Display Material and TechnologySchool of Materials Science and EngineeringSun Yat-sen UniversityGuangzhou 510275China Huzhou Key Laboratory of Environmental Functional Materials and Pollution Control School of EngineeringHuzhou UniversityHuzhou 313000China Department of Industrial and Systems Engineering Research Institute for Advanced ManufacturingThe Hong Kong Polytechnic UniversityHong Kong 999077China Department of Applied Physics The Hong Kong Polytechnic UniversityHong Kong 999077China Shanghai Key Laboratory of High-resolution Electron Microscopy ShanghaiTech UniversityShanghai 201210China

Armchair graphene nanoribbons(AGNRs)with sub-nanometer width are potential materials for the fabrication of novel nanodevices thanks to their moderate direct band *** are usually synthesized by polymerizing precursor molecules on substrate ***,it is time-consuming and not suitable for large-scale *** can also be grown by transforming precursor molecules inside single-walled carbon nanotubes(SWCNTs)via furnace annealing,but the obtained AGNRs are normally *** this work,microwave heating is applied for transforming precursor molecules into *** fast heating process allows synthesizing the AGNRs in *** different molecules were successfully transformed into AGNRs,suggesting that it is a universal *** importantly,as demonstrated by Raman spectroscopy,aberrationcorrected high-resolution transmission electron microscopy and theoretical calculations,less twisted AGNRs are synthesized by the microwave heating than the furnace *** results reveal a route for rapid production of AGNRs in large scale,which would benefit future applications in novel AGNRs-based semiconductor devices.

关键词： armchair graphene nanoribbons(AGNRs) microwave heating single-walled carbon nanotubes(SWCNTs) Raman spectroscopy

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Linear/branched Block Polyethylene Produced by a-Diimine Nickel(Ⅱ)Catalyst and Bis(phenoxy-imine)Zirconium Binary Catalyst System in the Presence of Diethyl Zinc

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Chinese Journal of Polymer Science 2021年第12期39卷 1581-1589页

作者： Ding-Ding Zhao Yan-Hui Hou Ke-Ning Zong Mi-Mi Cui Bin-Yuan Liu Min Yang Hebei Key Laboratory of Functional Polymers Institute of Polymer Science and EngineeringHebei University of TechnologyTianjin 300130China State Key Laboratory of Separation Membranes and Membrane Processes School of Material Science and EngineeringTiangong UniversityTianjin 300160China

In order to promote development of linear/branched block polyethylenes based on new catalytic systems,we synthesized a novel *** nickel(Ⅱ)complex with isopropyl substituents on ortho-N-aryl and hydroxymethyl phenyl substituents on para-Naryl *** activity of a-dimine nickl(Ⅱ)catalyst was 3.02x10^(6)g-mol_(ni)^(-1)·h^(-1) at 70℃,and resultant polyethylene possessed 135/1000C *** linear/branched block polyethylenes were synthesized from ethylene polymerization catalyzed by the a-dimine nicke(Ⅱ)complex/bis(phenoxy-imine)zirconium in the presence of diethyI *** the addition of ZnEtz(from 0 to 400),the melting peak of resultant polyethylene changed from a single melting peak to bimodal melting *** molecular weights of resultant polyethylene ranging from 26.8 kg/mol to 17.1 kg/mol and PDI values varying gradually from 24.4 to 15.2 were obtained vla adjusting ZnEt;*** molar ratio of two *** addition,the branching degree of the polyethylene increased from 13/1000C to 56/1000 with the increase of the proportion of a dimine nickel(Ⅱ)*** this binary catalyst system,the reaction temperature of chain shutting polymerization can be carried out at 70℃,which is more conducive to industrial application.

关键词： Chain shuttling polymerization Linear/branched block polyethylene a-Diimine nickel Bis(phenoxy-imine)zirconium Ethylene

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A new insight into LPSO phase transformation and mechanical properties uniformity of large-scale Mg-Gd-Y-Zn-Zr alloy prepared by multi-pass friction stir processing

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Journal of Magnesium and Alloys 2024年第5期12卷 2041-2056页

作者： Xiaohu Guan Wen Wang Ting Zhang Pai Peng Qiang Liu Peng Han Ke Qiao Jun Cai Liqiang Wang Kuaishe Wang School of Metallurgical Engineering National and Local Joint Engineering Research Center for Functional Materials ProcessingXi’an University of Architecture and TechnologyNo.13 Yanta RoadXi’anShaanxi 710055China Xi’an Rare Metal Materials Institute Co.Ltd Xi’an 710016China State Key Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityNo.800 Dongchuan RoadShanghai 200240China

A large-scale fine-grained Mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(MFSP)technology in this *** structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was ***,a quantitative relationship between the microstructure and tensile yield strength was *** results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were *** IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute *** severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO *** MFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 MPa,305 MPa and 18.0% *** refinement and LPSO phase strengthening were the major strengthening mechanisms for the MFSP *** particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in *** result opposes the widely accepted notion that IZ is a weak region in MFSP-prepared large-scale fine-grained plate.

关键词： Friction stir processing Multi-pass Mg-Gd-Y-Zn-Zr alloy LPSO phase transformation Mechanical properties

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Challenges in Photocatalytic Carbon Dioxide Reduction

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Precision Chemistry 2024年第2期2卷 49-56页

作者： Guangfu Liao Guixiang Ding Bin Yang Chunxue Li National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials College of Material EngineeringFujian Agriculture and Forestry UniversityFuzhou 350002China School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering Shihezi UniversityShihezi 832003China College of Ecological Environment and Urban Construction Fujian University of TechnologyFuzhou 350118China

An energy crisis and significant anthropogenic CO_(2)emissions as a result of rising fossil fuel consumption have caused a rapid increase in global *** of the best solutions to these two issues is thought to be the photocatalytic reduction of CO_(2)into value-added carbon-containing *** this aspect,the main challenges mainly include the photocatalytic mechanism,reaction activity,and product selectivity,especially in ambiguous reaction pathways and product selectivity,an unclear charge transfer mechanism,and an overestimate of product ***,in this perspective,we attempt to exhibit the discussion and in-depth analysis of the possible reaction pathways and product selectivity,the specific charge transfer mechanism,and the origin of carbon-containing products in phtocatalytic CO_(2)***,the fundamentals for photocatalytic CO_(2)reduction are also ***,the state-of-the-art challenges and perspectives in CO_(2)photoreduction are highlighted and discussed in *** perspective is expected to evoke more research attention for the photocatalytic reduction of CO_(2)into value-added products.

关键词： Phtocatalytic CO_(2)reduction Reaction Pathways Product Selectivity Charge Transfer Mechanism Overestimate of Product Yield

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Pressure-stabilized electride Li10Si with superconducting and superionic behavior

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Physical Review B 2024年第13期110卷 134114页

作者： Qinfang Wang Wenwen Cui Weishuo Xu Kun Gao Jian Hao Jingming Shi Hanyu Liu Yinwei Li Laboratory of Quantum Functional Materials Design and Application School of Physics and Electronic Engineering Key Laboratory of Material Simulation Methods and Software of Ministry of Education and State Key Laboratory of Superhard Materials College of Physics Shandong Key Laboratory of Optical Communication Science and Technology School of Physical Science & Information Technology of

Electrides have attracted increasing interest due to their diversely physical properties, including low work function, high catalytic activity, as well as potential superconductivity. In this work, using first-principles crystal structure prediction method in combination with first-principles calculations, we uncovered seven thermodynamically stable electrides in the electron-rich Li-Si system at a pressure range of 25–100 GPa, namely C2/cLi5Si, CmcmLi6Si, P21/mLi7Si, ImmaLi7Si, C2/cLi8Si, CmcmLi9Si, and I222Li10Si. Among these predicted structures, five of them are superconductor. In particular, the superconducting critical temperature Tc of I222Li10Si was estimated to be approximately 15 K at 95 GPa. Our in-depth analysis shows that this high superconductivity is attributed to the strong coupling between the Li-p electrons and the Li-dominated phonon softening at low frequencies. Additionally, Li10Si undergoes a phase transition from solid state to superionic state at 60 GPa and 850 K, where Si atoms remain fixed to form the lattice, allowing for the diffusion of Li atoms within the interstitial position. Our results reveal the emergence of two distinct dynamic states of superconducting and superionic in this particular system, and the further experimental studies are thus stimulated.

关键词： Superconductors Density functional calculations Density functional theory First-principles calculations

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The 2^(nd)Asian Conference on Porphyrins,Phthalocyanines and Related materials

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Chinese Chemical Letters 2024年第7期35卷 1-3页

作者： Gaojie Zhu Zhen Yang Shijun Li Weihua Zhu Rui Cao Junlong Zhang Jianzhang Zhao Jonathan L.Sessler Xunjin Zhu Jianxin Song Yongshu Xie Jianzhuang Jiang Key Laboratory for Advanced Materials and Institute of Fine Chemicals School of Chemistry and Molecular EngineeringEast China University of Science&TechnologyShanghai 200237China College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material Technology of Ministry of EducationHangzhou Normal UniversityHangzhou 311121China School of Chemistry and Chemical Engineering Jiangsu UniversityZhenjiang 212013China Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationSchool of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi'an 710119China Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China Department of Chemistry The University of TexasAustinTexas 78712-1224United States Department of Chemistry and Institute of Advanced Materials Hong Kong Baptist UniversityHong Kong 999077China Key Laboratory of Chemical Biology and Traditional Chinese Medicine(Ministry of Educational of China) Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan ProvinceCollege of Chemistry and Chemical EngineeringHunan Normal UniversityChangsha 410081China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline MaterialsDepartment of Chemistry and Chemical EngineeringSchool of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083China

In the past decades,porphyrins,phthalocyanines and related materials have attracted significant attention due to their diverse and brilliant structures[1,2],as well as their unique electronic structures and photophysi... 详细信息

关键词： cyanine phthalocyanine Porphyrin

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