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Role of the lattice in the light-induced insulator-to-metal transition in vanadium dioxide

Physical Review Research 2020年第2期2卷 023076-023076页

作者： Cédric Weber Swagata Acharya Brian Cunningham Myrta Grüning Liangliang Zhang Hang Zhao Yong Tan Yan Zhang Cunlin Zhang Kai Liu Mark Van Schilfgaarde Mostafa Shalaby King's College London The Strand WC2R 2LS London United Kingdom School of Mathematics and Physics Queen's University Belfast Belfast BT7 1NN United Kingdom Key Laboratory of Terahertz Optoelectronics Beijing Advanced Innovation Center for Imaging Technology CNU Beijing 100048 China Beijing Key Laboratory for Precision Optoelectronic Measurement Instrument and Technology School of Optics and Photonics Beijing Institute of Technology Beijing 100081 China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China National Renewable Energy Laboratories Golden Colorado 80401 USA Swiss Terahertz Research-Zurich Technopark 8005 Zurich Switzerland and Park Innovaare 5234 Villigen Switzerland

Vanadium dioxide is a model material system which exhibits a metal-to-insulator transition at 67∘C. This holds potential for future ultrafast switching in memory devices but typically requires a purely electronic process to avoid the slow lattice response. The role of lattice vibrations is thus important, but it is not fully understood and it has been a long-standing source of controversy. We use ultrafast spectroscopy and ab initio quantum calculations to study the mechanism responsible for the transition. We identify an atypical Peierls vibrational mode associated with the transition and study its associated properties. Our findings led to theoretical prediction of a new electron-phonon pathway for a purely reversible electronic transition in a true bistable fashion under specific conditions. This transition is very atypical, as it involves purely chargelike excitations and requires only small nuclear displacement and might prompt future experimental investigations.

关键词： Electrical properties Electronic structure First-principles calculations Metal-insulator transition Peierls transition Vanadates Ultrafast pump-probe spectroscopy

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Unveiling the Electrolyte Cations Dependent Kinetics on CoOOH-Catalyzed Oxygen Evolution Reaction

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Angewandte Chemie 2023年第49期135卷

作者： Hongnan Jia Na Yao Can Yu Hengjiang Cong Prof. Dr. Wei Luo College of Chemistry and Molecular Sciences Wuhan University Hubei 430072 Wuhan P. R. China Contribution: Data curation (equal) Formal analysis (equal) Writing - original draft (equal) State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile University Hubei 430073 Wuhan P. R. China Contribution: Data curation (equal) Formal analysis (equal) Software (lead) Writing - original draft (equal) Institute of High Energy Physics Chinese Academy of Science Beijing 100049 P. R. China Contribution: Data curation (supporting) Formal analysis (supporting) Contribution: Conceptualization (lead) Funding acquisition (lead) Investigation (lead) Supervision (lead) Writing - original draft (equal) Writing - review & editing (lead)

The electrolyte cations-dependent kinetics have been widely observed in many fields of electrocatalysis, however, the exact mechanism of the influence on catalytic performance is still a controversial topic of considerable discussion. Herein, combined with operando X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM), we verify that the electrolyte cations could intercalate into the layer of pristine CoOOH catalyst during the oxygen evolution reaction (OER) process, while the bigger cations lead to enlarged interlayer spacing and increased OER activity, following the order Cs + >K + >Na + >Li + . X-ray absorption spectroscopy (XAS), in situ Raman, in situ Ultraviolet-visible (UV/Vis) spectroscopy, in situ XAS spectroscopy, cyclic voltammetry (CV), and theoretical calculations reveal that the intercalation of electrolyte cations efficiently modify the oxidation states of Co by enlarging the Co−O bonds, which in turn enhance the d -band center of Co, optimize the adsorption strength of oxygen intermediates, facilitate the formation of OER active Co(IV) species, and reduce the energy barrier of the rate-determing step (RDS), thereby enhancing the OER activity. This work not only provides an informative picture to understand the complicated dependence of OER kinetics on electrolyte cations, but also sheds light on understanding the mechanism of other electrolyte cation-targeted electrocatalysis.

关键词： Cation Effect Cation Intercalation CoOOH High-Valent Cobalt Oxygen Evolution Reaction

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Robust Ferromagnetism in Highly Strained SrCoO3 Thin Films

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Physical Review X 2020年第2期10卷 021030-021030页

作者： Yujia Wang Qing He Wenmei Ming Mao-Hua Du Nianpeng Lu Clodomiro Cafolla Jun Fujioka Qinghua Zhang Ding Zhang Shengchun Shen Yingjie Lyu Alpha T. N’Diaye Elke Arenholz Lin Gu Cewen Nan Yoshinori Tokura Satoshi Okamoto Pu Yu State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics Tsinghua University Beijing 100084 China Frontier Science Center for Quantum Information Beijing 100084 China Department of Physics Durham University Durham DH1 3LE United Kingdom Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Science Beijing 100190 China Graduate School of Pure and Applied Science University of Tsukuba Tsukuba Ibaraki Japan State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Advanced Light Source Lawrence Berkeley National Laboratory Berkeley California 94720 USA RIKEN Center for Emergent Matter Science (CEMS) Wako Saitama 351-0198 Japan Tokyo College and Department of Applied Physics University of Tokyo Tokyo 113-8656 Japan

Epitaxial strain provides important pathways to control the magnetic and electronic states in transition-metal oxides. However, the large strain is usually accompanied by a strong reduction of the oxygen-vacancy formation energy, which hinders the direct manipulation of their intrinsic properties. Here, using a postdeposition ozone annealing method, we obtain a series of oxygen stoichiometric SrCoO3 thin films with the tensile strain up to 3.0%. We observe a robust ferromagnetic ground state in all strained thin films, while interestingly the tensile strain triggers a distinct metal-to-insulator transition along with the increase of the tensile strain. The persistent ferromagnetic state across the electrical transition therefore suggests that the magnetic state is directly correlated with the localized electrons, rather than the itinerant ones, which then calls for further investigation of the intrinsic mechanism of this magnetic compound beyond the double-exchange mechanism.

关键词： Epitaxial strain Ferromagnetism Metal-insulator transition Ferromagnets Transition metal oxides Epitaxy First-principles calculations Magnetization measurements X-ray magnetic circular dichroism

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A high-strength mineralized collagen bone scaffold for large-sized cranial bone defect repair in sheep

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Regenerative Biomaterials 2018年第5期5卷 283-292页

作者： Shuo Wang Zhijun Zhao Yongdong Yang Antonios G.Mikos Zhiye Qiu Tianxi Song Fuzhai Cui XiumeiWang Chunyang Zhang State Key Laboratory of New Ceramics and Fine Processing Key Laboratory of Advanced Materials of Ministry of EducationSchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Department of Neurosurgery The First Affiliated Hospital of Baotou Medical SchoolBaotou 014010China Dongzhimen Hospital Affiliated Beijing University of Chinese Medicine Beijing 100700China Department of Bioengineering Rice UniversityHoustonTX 77030USA Beijing Allgens Medical Science and Technology Co. Ltd.Beijing 100176China

Large-sized cranial bone defect repair presents a great challenge in the *** ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support,excellent biocompatibility,good osseointegration and biodegradability as *** this study,a high-strength mineralized collagen(MC)bone scaffold was developed with biomimetic composition,microstructure and mechanical properties for the repair of sheep largesized cranial bone defects in comparison with two traditional cranioplasty materials,polymethyl methacrylate and titanium *** compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical *** strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact *** vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells(hBMSC)had good viability,attachment and proliferation on the compact MC scaffold indicating its excellent *** adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone *** results were investigated by gross observation,computed tomography scanning as well as histological *** in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone *** results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.

关键词： mineralized collagen cranial bone defect bone regeneration sheep cranioplasty materials

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An Anomalous Electron Configuration Among 3dTransition Metal Atoms

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Angewandte Chemie 2022年第7期135卷

作者： Zhexin Tang Tongtong Shang Han Xu Ting Lin Ang Gao Weiguang Lin Xinyan Li Shiyu Wang Botao Yu Fanqi Meng Qinghua Zhang Xuefeng Wang Dong Su Qingbo Meng Lijun Wu Lin Gu Ce-Wen Nan Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences 100190 Beijing P. R. China School of Physical Sciences University of Chinese Academy of Sciences 100049 Beijing P. R. China State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University 100084 Beijing P. R. China Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University 100084 Beijing P. R. China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences 100049 Beijing P. R. China Condensed Matter Physics and Materials Science Division Brookhaven National Laboratory 11973 Upton NY USA

Physical properties of materials are mainly determined by valence electron configurations, where different valence shells would induce divergent phenomena. In compounds containing Sc 2+ , 3 d electron occupancy is expected, the same as other transition metal atoms like Ti 3+ . But this situation still awaits experimental verification in inorganic materials. Here, we selected ScS to measure the valence electron density and orbital population of Sc 2+ through delicate quantitative convergent-beam electron diffraction. With the absence of 3 d orbital features around Sc-atom sites and the nearly bare population of t 2g orbital, the unintuitive occupation of 4 s orbital in Sc 2+ is concluded. It should be the first time to report such a special electron configuration in a transition metal compound, in which 4 s rather than 3 d orbital is preferred. Our findings reveal the distinct behavior of Sc and probable ways to modulate material properties by controlling electron orbitals.

关键词： Electron Configuration Electron Density Distribution Electron Microscopy Quantitative Convergent-Beam Electron Diffraction Scandium

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Author Correction: Real-space measurement of orbital electron populations for Li1-xCoO2

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Nature Communications 2022年第1期13卷 1页

作者： Tongtong Shang Dongdong Xiao Xiaohui Rong Ang Gao Ting Lin Zhexin Tang Xiaozhi Liu Xinyan Li Qinghua Zhang Ruijuan Xiao Xuefeng Wang Dong Su Yong-Sheng Hu Hong Li Lin Gu Fanqi Meng Ce-Wen Nan Yuren Wen Qian Yu Ze Zhang Vaclav Petricek Lijun Wu Yimei Zhu Jian-Min Zuo Jing Zhu Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Songshan Lake Materials Laboratory Dongguan 523808 P. R. China State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 P. R. China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 P. R. China Department of Materials Science and Engineering Center of Electron Microscopy and State Key Laboratory of Silicon Materials Zhejiang University Hangzhou 310027 P. R. China Institute of Physics Academy of Sciences of the Czech Republic Praha 180 40 Czech Republic Condensed Matter Physics and Materials Science Division Brookhaven National Laboratory Upton New York 11973 USA Department of Materials Science and Engineering University of Illinois at Urbana Champaign 1304 W Green St Urbana 61801 USA Beijing National Center for Electron Microscopy Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 P. R. China

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Silk Fibroin Scaffolds Direct Neural and Glial Differentiation from Embryonic Stem Cells

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医用生物力学 2019年第A1期34卷 163-163页

作者： Yawen Liao Peng Tang Yao Zhang Zhanao Hu Yongning Zhang Shangbang Gao Qiang Zhang Ning Wang Laboratory for Cellular Biomechanics and Regenerative Medicine Department of Biomedical EngineeringCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhan430074China State Key Laboratoryfor Hubei New Textile Materials and Advanced Processing Technology School of Textile Science and EngineeringWuhan Textile UniversityWuhan430074China Key Laboratory of Molecular Biophysics of the Ministry of Education International Research Center for Sensory Biology and Technology of the Ministry of Science and TechnologyHuazhongUniversity of Science and TechnologyWuhan430074China Department of Mechanical Science and Engineering College of EngineeringUniversity of Illinois at Urbana-ChampaignUrbanaIL61801USA

Spinal cord injury repair is one of the major challenges in medicine,as it can lead to permanent loss of function of central nervous system and damage to other function of the *** cell transplantation together with tissue engineering is increasingly becoming a potential choice of ***,direct transplantation of stem cells without scaffolds has yielded poor clinical *** we show a strategy of using mouse embryonic stem cells(ESCs)cultured within a silk fibroin(SF)based,three-dimensional scaffold with oriented channels by a directional temperature field freezing technique and *** find that the ESCs maintained proliferation and migrated in the scaffolds and the cells migrated fastest along the SF *** scaffolds contributed to ESC differentiation into neural and glial cell like cells and expressions of the neural and glial cell markers MAP2 and GFAP were greatly elevated when retinoic acid was used as an inducing *** results suggest that this approach may offer some hope in the future for spinal cord injury repair using SF scaffolds and ESCs.

关键词： Silk Fibroin Scaffolds Direct Neural Glial Differentiation Embryonic Stem Cells

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A Non-Conjugated Polymer Acceptor for Efficient and Thermally Stable All-Polymer Solar Cells

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Angewandte Chemie 2020年第45期132卷

作者： Fan Q. Su W. Chen S. Liu T. Zhuang W. Ma R. Wen X. Yin Z. Luo Z. Guo X. Hou L. Moth-Poulsen K. Li Y. Zhang Z. Yang C. Yu D. Yan H. Zhang M. Wang E. Department of Chemistry and Chemical Engineering Chalmers University of Technology Göteborg 41296 Sweden Laboratory of Advanced Optoelectronic Materials College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials Siyuan Laboratory Department of Physics Jinan University Guangzhou 510632 China Department of Energy Engineering School of Energy and Chemical Engineering Low Dimensional Carbon Materials Center Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 South Korea MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems CQU-NUS Renewable Energy Materials & Devices Joint Laboratory School of Energy & Power Engineering Chongqing University Chongqing 400044 China Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction Hong Kong University of Science and Technology Clear Water Bay Kowloon999077 Hong Kong Guangdong Research Center for Special Building Materials and Its Green Preparation Technology Advanced Research Center for Polymer Processing Engineering of Guangdong Province Guangdong Industry Polytechnic Guangzhou 510300 China State Key Laboratory of Organic/Inorganic Composites Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Chemistry and Bioscience Aalborg University Aalborg East 9220 Denmark Sino-Danish Center for Education and Research Aarhus 8000 Denmark School of Materials Science and Engineering Zhengzhou University Zhengzhou 450001 China

A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >105 cm−1, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments. © 2020 The Authors. Published by Wiley-VCH GmbH

关键词： all-polymer solar cells non-conjugated polymer acceptors power conversion efficiency thermal stability thioalkyl chain linkages

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Robust ferromagnetism in highly strained SrCoO3 thin films

arXiv

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arXiv 2020年

作者： Wang, Yujia He, Qing Ming, Wenmei Du, Mao-Hua Lu, Nianpeng Cafolla, Clodomiro Fujioka, Jun Zhang, Qinghua Zhang, Ding Shen, Shengchun Lyu, Yingjie N'Diaye, Alpha T. Arenholz, Elke Gu, Lin Nan, Cewen Tokura, Yoshinori Okamoto, Satoshi Yu, Pu State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China Frontier Science Center for Quantum Information Beijing100084 China Department of Physics Durham University DurhamDH1 3LE United Kingdom Materials Science and Technology Division Oak Ridge National Laboratory Oak RidgeTN37831 United States Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Science Beijing100190 China Graduate school of Pure and Applied Science University of Tsukuba TsukubaIbaraki Japan State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing100084 China Advanced Light Source Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Wako Saitama351-0198 Japan Tokyo College Department of Applied Physics University of Tokyo Tokyo113-8656 Japan

Epitaxial strain provides important pathways to control the magnetic and electronic states in transition metal oxides. However, the large strain is usually accompanied by a strong reduction of the oxygen vacancy formation energy, which hinders the direct manipulation of their intrinsic properties. Here using a post-deposition ozone annealing method, we obtained a series of oxygen stoichiometric SrCoO3 thin films with the tensile strain up to 3.0%. We observed a robust ferromagnetic ground state in all strained thin films, while interestingly the tensile strain triggers a distinct metal to insulator transition along with the increase of the tensile strain. The persistent ferromagnetic state across the electrical transition therefore suggests that the magnetic state is directly correlated with the localized electrons, rather than the itinerant ones, which then calls for further investigation of the intrinsic mechanism of this magnetic compound beyond the double-exchange mechanism. Copyright © 2020, The Authors. All rights reserved.

关键词： Tensile strain

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Giant power output in lead-free ferroelectrics by shock-induced phase transition

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Physical Review materials 2019年第3期3卷 035401-035401页

作者： Zhipeng Gao Wei Peng Bin Chen Simon A. T. Redfern Ke Wang Baojin Chu Qiang He Yi Sun Xuefeng Chen Hengchang Nie Wen Deng Lingkong Zhang Hongliang He Genshui Wang Xianlin Dong National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics China Academy of Engineering Physics Mianyang 621900 China CAS Key Laboratory of Inorganic Functional Materials and Devices Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China Department of Earth Sciences University of Cambridge Cambridge CB2 3EQ United Kingdom State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Information and Quantum Physics University of Science and Technology of China Hefei 230026 China The State Key Lab of High Performance and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

The force-electric effect in ferroelectrics is characterized by the release of bound charge during pressure/shock-induced depolarization. In contrast to other electrical energy storage systems, the charge-storage/release by the force-electric effect of ferroelectrics is determined by polarization switching or polar-nonpolar phase transition. This offers a further set of options for materials design in the realm of energy conversion, especially for the high power density applications. Here, we report that a ferroelectric ceramic, Na0.5Bi0.5TiO3 (NBT), can generate a high power output (3.04×108W/kg) under shock compression, which is one of the highest values achieved by the force-electric effect. The in situ synchrotron x-ray diffraction studies reveal that this power output mainly arises from a polar-nonpolar phase transition (rhombohedral-orthorhombic). First-principles calculations show that this is a first-order phase transition that undergoes two-step structure changes. These results extend the application of the force-electric effect and are a key step in understanding the phase transition behaviors of NBT under high pressure.

关键词： Ferroelectricity Phase transitions Pressure effects

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