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arXiv 2020年

作者： Deng, Bing Wang, Binbin Li, Ning Li, Rongtan Wang, Yani Tang, Jilin Fu, Qiang Tian, Zhen Gao, Peng Xue, Jiamin Peng, Hailin College of Chemistry and Molecular Engineering Peking University Beijing100871 China School of Physical Science and Technology ShanghaiTech University Shanghai201210 China International Center for Quantum Materials Electron Microscopy Laboratory School of Physics Peking University Beijing100871 China Collaborative Innovation Center of Quantum Matter Beijing100871 China Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian116023 China Academy for Advanced Interdisciplinary Studies Peking University Beijing100871 China

Stacking order has strong influence on the coupling between the two layers of twisted bilayer graphene (BLG), which in turn determines its physical properties. Here, we report the investigation of the interlayer coupling of the epitaxially grown single-crystal 30° twisted BLG on Cu(111) at the atomic scale. The stacking order and morphology of BLG is controlled by a rationally designed two-step growth process, that is, the thermodynamically controlled nucleation and kinetically controlled growth. The crystal structure of the 30°-twisted bilayer graphene (30°-tBLG) is determined to have the quasicrystal like symmetry. The electronic properties and interlayer coupling of the 30°-tBLG is investigated using scanning tunneling microscopy (STM) and spectroscopy (STS). The energy-dependent local density of states (DOS) with in-situ electrostatic doping shows that the electronic states in two graphene layers are decoupled near the Dirac point. A linear dispersion originated from the constituent graphene monolayers is discovered with doubled degeneracy. This study contributes to controlled growth of twist-angle-defined BLG, and provides insights of the electronic properties and interlayer coupling in this intriguing system. Copyright © 2020, The Authors. All rights reserved.

关键词： Electronic structure

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Very-high-energy gamma-ray detection and long-term multi-wavelength view of the flaring blazar B2 1811+31

arXiv

引用

arXiv 2025年

作者： Abe, K. Abe, S. Abhir, J. Abhishek, A. Acciari, V.A. Aguasca-Cabot, A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Engels, A. Arbet Arcaro, C. Asano, K. Babić, A. de Almeida, U. Barres Barrio, J.A. Barrios-Jiménez, L. Batković, I. Baxter, J. González, J. Becerra Bednarek, W. Bernardini, E. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Bronzini, E. Burelli, I. Campoy-Ordaz, A. Carosi, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Cerasole, D. Ceribella, G. Chilingarian, A. Cifuentes, A. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Ammando, F. D’Amico, G. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. de Menezes, R. Delfino, M. Delgado, J. Mendez, C. Delgado Di Pierro, F. Di Tria, R. Di Venere, L. Dinesh, A. Prester, D. Dominis Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsaesser, D. Escudero, J. Fariña, L. Foffano, L. Font, L. Fröse, S. Fukazawa, Y. López, R.J. García Garczarczyk, M. Gasparyan, S. Gaug, M. Paiva, J.G. Giesbrecht Giglietto, N. Giordano, F. Gliwny, P. Gradetzke, T. Grau, R. Green, D. Green, J.G. Günther, P. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Llorente, J. Herrera Hrupec, D. Imazawa, R. Israyelyan, D. Itokawa, T. Martínez, I. Jiménez Quiles, J. Jiménez Jormanainen, J. Kankkunen, S. Kayanoki, T. Kerszberg, D. Khachatryan, M. Kluge, G.W. Kobayashi, Y. Konrad, J. Kouch, P.M. Kubo, H. Kushida, J. Láinez, M. Lamastra, A. Lindfors, E. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Lulić, L. Lyard, E. Majumdar, P. Makariev, M. Maneva, G. Manganaro, M. Mangano, S. Mannheim, K. Mariotti, M. Martínez, M. Maruševec, P. Mas-Aguilar, A. Mazin, D. Menchiari, S. Mender, S. Miceli, D. Miranda, J.M. Mirzoyan, R. González, M. Molero Molina, E. Mondal, H.A. Moralejo, A. Nakamori, T. Nanci, C. Neustroev, V. Nickel, L. Rosillo, M. Nievas Nigro, C. Nikolić, L. Nilsson, K. Nishijima, K. Ekoume, T. Njoh Noda, K. Japanese MAGIC Group Department of Physics Tokai University Kanagawa Hiratsuka259-1292 Japan The University of Tokyo Chiba Kashiwa277-8582 Japan ETH Zürich ZürichCH-8093 Switzerland Università di Siena INFN Pisa SienaI-53100 Italy Bellaterra BarcelonaE-08193 Spain Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik GarchingD-85748 Germany Università di Padova INFN PadovaI-35131 Italy Zagreb10000 Croatia URCA RJ Rio de Janeiro22290-180 Brazil IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain Instituto de Astrofísica de Canarias and Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa PisaI-56126 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari BariI-70125 Italy Armenian MAGIC Group A. Alikhanyan National Science Laboratory Yerevan0036 Armenia Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy Croatian MAGIC Group University of Rijeka Faculty of Physics Rijeka51000 Croatia Universität Würzburg WürzburgD-97074 Germany Technische Universität Dortmund DortmundD-44221 Germany Japanese MAGIC Group: Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan ZeuthenD-15738 Germany Armenian MAGIC Gro

Context. Among the blazars whose emission has been detected up to very-high-energy (VHE;100 GeV 14 δD cm to the size of the emission region responsible for the γ-ray flare, δD being the relativistic Doppler factor of the region. During the 2020 high state, the average spectrum became harder in the HE γ-ray band compared to the low states. A similar behaviour has been observed in X rays. Conversely, during different activity periods, we find harder-when-brighter trends in X rays and a hint of softer-when-brighter trends at HE γ rays. Long-term HE γ-ray and optical correlation indicates the same emission regions dominate the radiative output in both ranges, whereas the evolution at 15 GHz shows no correlation with the fluxes at higher frequencies. We test one-zone and two-zone synchrotron-self-Compton models for describing the broad-band spectral energy distribution during the 2020 flaring state and investigate the self-consistency of the proposed scenario. Copyright © 2025, The Authors. All rights reserved.

关键词： Synchrotron radiation

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Author Correction: Coexistence of ferromagnetism, antiferromagnetism, and superconductivity in magnetically anisotropic (Eu,La)FeAs2

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npj Quantum Materials 2021年第1期6卷 1页

作者： Jia Yu Lisi Li Zengjia Liu Bing Shen Meng Wang Congcong Le Zhiwei Li Bo Zhang Tong Liu Binbin Ruan Zhi’an Ren Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou China Max Planck Institute for Chemical Physics of Solids Dresden Germany Key Lab for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou University Lanzhou China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China School of Physical Sciences University of Chinese Academy of Sciences Beijing China

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Controlling the Valence-Electron Arrangement of Nickel Active Centers for Efficient Hydrogen Oxidation Electrocatalysis

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Angewandte Chemie 2022年第32期134卷

作者： Prof. Xu Zhao Dr. Xiangyang Li Lulu An Prof. Lirong Zheng Prof. Jinlong Yang Prof. Deli Wang Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education) Hubei Key Laboratory of Material Chemistry and Service Failure School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China Hefei National Laboratory for Physical Sciences at the Microscale Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 P. R. China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 P. R. China

The valence-electron arrangement of heterogeneous catalysts can significantly affect the binding behavior of absorbates. However, it remains a challenge to understand the role of the valence-electron arrangement in electrocatalysis, which limits its utilization as a tool to design efficient electrocatalysts. Here, we describe experiments in which the valence-electron arrangement of Ni active centers for hydrogen oxidation is controlled precisely by using Ni-vacancy-enriched Ni 3 N as a platform. These Ni vacancies can promote the valence-electron delocalization of OH-adsorption centers to enhance the Ni ds –O 2 p valence-electron-orbital interaction with elevated OH adsorption. Meanwhile, the deficit of valence-electrons of H-adsorption centers at Ni vacancies can lower Ni ds –H 1 s interaction with weakened H binding. Relative to Ni 3 N poor in vacancies, the Ni-vacancy-enriched Ni 3 N showed a mass activity enhanced by 15-fold. This strategy paves a rational way to design efficient catalysts by finely tuning the valence-electron arrangement.

关键词： Adsorption Electrocatalysis Nickel Orbital Interactions Valence Electrons

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Measurements of q2Moments of Inclusive B → Xc+νDecays with Hadronic Tagging

arXiv

引用

arXiv 2021年

作者： Van Tonder, R. Cao, L. Sutcliffe, W. Welsch, M. Bernlochner, F.U. Adachi, I. Aihara, H. Asner, D.M. Aushev, T. Ayad, R. Babu, V. Behera, P. Belous, K. Bennett, J. Bessner, M. Bhardwaj, V. Bilka, T. Biswal, J. Borah, J. Bozek, A. Bračko, M. Branchini, P. Browder, T.E. Budano, A. Campajola, M. Červenkov, D. Chang, M.-C. Chang, P. Chekelian, V. Chen, A. Cheon, B.G. Chilikin, K. Cho, H.E. Cho, K. Cho, S.-J. Choi, S.-K. Choi, Y. Choudhury, S. Cinabro, D. Cunliffe, S. Das, S. Dash, N. De Nardo, G. De Pietro, G. Dhamija, R. Di Capua, F. Dingfelder, J. Doležal, Z. Dong, T.V. Epifanov, D. Ferber, T. Ferlewicz, D. Fulsom, B.G. Garg, R. Gaur, V. Gabyshev, N. Garmash, A. Giri, A. Goldenzweig, P. Graziani, E. Gu, T. Gudkova, K. Hadjivasiliou, C. Hara, T. Hartbrich, O. Hayasaka, K. Hayashii, H. Hou, W.-S. Hsu, C.-L. Inami, K. Ishikawa, A. Itoh, R. Iwasaki, M. Iwasaki, Y. Jacobs, W.W. Jia, S. Jin, Y. Joo, K.K. Kaliyar, A.B. Kang, K.H. Kato, Y. Kiesling, C. Kim, C.H. Kim, D.Y. Kim, K.-H. Kim, S.H. Kim, Y.-K. Kinoshita, K. Kodyš, P. Konno, T. Korobov, A. Korpar, S. Kovalenko, E. Križan, P. Kroeger, R. Krokovny, P. Kuhr, T. Kulasiri, R. Kumara, K. Kwon, Y.-J. Lange, J.S. Laurenza, M. Lee, S.C. Li, J. Li, L.K. Li, Y.B. Li Gioi, L. Libby, J. Al Said, S. Bahinipati, S. Lieret, K. Liventsev, D. MacQueen, C. Masuda, M. Matsuda, T. Matvienko, D. McNeil, J.T. Merola, M. Miyabayashi, K. Mizuk, R. Mohanty, G.B. Moon, T.J. Mussa, R. Nakao, M. Natkaniec, Z. Natochii, A. Nayak, L. Nayak, M. Niiyama, M. Nisar, N.K. Nishida, S. Ogawa, S. Ono, H. Onuki, Y. Oskin, P. Pakhlov, P. Pakhlova, G. Pardi, S. Park, H. Park, S.-H. Paul, S. Pedlar, T.K. Pestotnik, R. Piilonen, L.E. Podobnik, T. Prencipe, E. Prim, M.T. Rostomyan, A. Rout, N. Russo, G. Sahoo, D. Sakai, Y. Sandilya, S. Sangal, A. Santelj, L. Sanuki, T. Savinov, V. Schnell, G. Schueler, J. Schwanda, C. Department of Physics University of the Basque Country UPV/EHU Bilbao48080 Spain University of Bonn Bonn53115 Germany Brookhaven National Laboratory UptonNY11973 United States Budker Institute of Nuclear Physics SB RAS Novosibirsk630090 Russia Faculty of Mathematics and Physics Charles University Prague121 16 Czech Republic Chonnam National University Gwangju61186 Korea Republic of University of Cincinnati CincinnatiOH45221 United States Deutsches Electronen-Synchrotron Hamburg22607 Germany University of Florida GainesvilleFL32611 United States Department of Physics Fu Jen Catholic University Taipei24205 Taiwan Institute of Modern Physics Fudan University Shanghai200443 China Justus-Liebig-Universität Gießen Gießen 35392 Germany Gifu University Gifu501-1193 Japan Hayama240-0193 Japan Gyeongsang National University Jinju52828 Korea Republic of Department of Physics Institute of Natural Sciences Hanyang University Seoul04763 Korea Republic of University of Hawaii HonoluluHI96822 United States Tsukuba305-0801 Japan National Research University Higher School of Economics Moscow101000 Russia Forschungszentrum Jülich Jülich52425 Germany IKERBASQUE Basque Foundation for Science Bilbao48013 Spain Indian Institute of Science Education and Research Mohali SAS Nagar 140306 India Indian Institute of Technology Bhubaneswar Satya Nagar 751007 India Indian Institute of Technology Guwahati Assam 781039 India Indian Institute of Technology Hyderabad Telangana 502285 India Indian Institute of Technology Madras Chennai600036 India Indiana University BloomingtonIN47408 United States Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Institute of High Energy Physics Vienna1050 Austria Institute for High Energy Physics Protvino142281 Russia INFN - Sezione di Napoli NapoliI-80126 Italy INFN - Sezione di Roma Tre RomaI-00146 Italy INFN - Sezione di Torino TorinoI-10125 Italy Advanced Scienc

We present the measurement of the first to fourth order moments of the four-momentum transfer squared, q2, of inclusive B → Xc+νdecays using the full Belle data set of 711 fb-1of integrated luminosity at the ϒ(4S) resonance where = e, μ. The determination of these moments and their systematic uncertainties open new pathways to determine the absolute value of the CKM matrix element Vcbusing a reduced set of matrix elements of the heavy quark expansion. In order to identify and reconstruct the Xcsystem, we reconstruct one of the two B-mesons using machine learning techniques in fully hadronic decay modes. The moments are measured with progressively increasing threshold selections on q2starting with a lower value of 3.0 GeV2in steps of 0.5 GeV2up to a value of 10.0 GeV2. The measured moments are further unfolded, correcting for reconstruction and selection effects as well as QED final state radiation. We report the moments separately for electron and muon final states and observe no lepton flavor universality violating effects. © 2021, CC BY.

关键词： Germanium alloys

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Precessing jet nozzle connecting to a spinning black hole in M87

arXiv

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arXiv 2023年

作者： Cui, Yuzhu Hada, Kazuhiro Kawashima, Tomohisa Kino, Motoki Lin, Weikang Mizuno, Yosuke Ro, Hyunwook Honma, Mareki Yi, Kunwoo Yu, Jintao Park, Jongho Jiang, Wu Shen, Zhiqiang Kravchenko, Evgeniya Algaba, Juan-Carlos Cheng, Xiaopeng Cho, Ilje Giovannini, Gabriele Giroletti, Marcello Jung, Taehyun Lu, Ru-Sen Niinuma, Kotaro Oh, Junghwan Ohsuga, Ken Sawada-Satoh, Satoko Sohn, Bong Won Takahashi, Hiroyuki R. Takamura, Mieko Tazaki, Fumie Trippe, Sascha Wajima, Kiyoaki Akiyama, Kazunori An, Tao Asada, Keiichi Buttaccio, Salvatore Byun, Do-Young Cui, Lang Hagiwara, Yoshiaki Hirota, Tomoya Hodgson, Jeffrey Kawaguchi, Noriyuki Kim, Jae-Young Lee, Sang-Sung Lee, Jee Won Lee, Jeong Ae Maccaferri, Giuseppe Melis, Andrea Melnikov, Alexey Migoni, Carlo Oh, Se-Jin Sugiyama, Koichiro Wang, Xuezheng Zhang, Yingkang Chen, Zhong Hwang, Ju-Yeon Jung, Dong-Kyu Kim, Hyo-Ryoung Kim, Jeong-Sook Kobayashi, Hideyuki Li, Bin Li, Guanghui Li, Xiaofei Liu, Zhiyong Liu, Qinghui Liu, Xiang Oh, Chung-Sik Oyama, Tomoaki Roh, Duk-Gyoo Wang, Jinqing Wang, Na Wang, Shiqiang Xia, Bo Yan, Hao Yeom, Jae-Hwan Yonekura, Yoshinori Yuan, Jianping Zhang, Hua Zhao, Rongbing Zhong, Weiye Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Tsung-Dao Lee Institute Shanghai Jiao Tong University 520 Shengrong Road Shanghai201210 China Astronomical Science Program The Graduate University for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Mizusawa VLBI Observatory National Astronomical Observatory of Japan 2-12 Hoshigaoka Mizusawa Iwate Oshu023-0861 Japan Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan Kogakuin University of Technology & Engineering Academic Support Center 2665-1 Nakano-machi Hachioji Tokyo192-0015 Japan South-Western Institute For Astronomy Research Yunnan University Kunming650500 China School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Institut für Theoretische Physik Goethe-Universität Frankfurt Max-von-Laue-Straße 1 Frankfurt am MainD-60438 Germany Korea Astronomy & Space Science Institute Daedeokdae-ro 776 Yuseong-gu Daejeon34055 Korea Republic of Department of Astronomy Yonsei University Yonsei-ro 50 Seodaemun-gu Seoul03722 Korea Republic of Department of Astronomy Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan Department of Physics and Astronomy Seoul National University Gwanak-gu Seoul08826 Korea Republic of Department of Information Countermeasure Air Force Early Warning Academy Wuhan430019 China Institute of Astronomy and Astrophysics Academia Sinica HiloHI96720 United States Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Beijing100101 China Moscow Institute of Physics and Technology Dolgoprudny Institutsky per. 9 Moscow141700 Russia Lebedev Physical Institute The Russian Academy of Sciences Leninsky prospekt 53 Moscow119991 Russia Department of Physics Faculty of Science U

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole 1–4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from General Relativity 5. With a baseline of 17 years of observations, there was a shift in the jet’s transverse position, possibly arising from an eight to ten-year quasi-periodicity 3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years in the position angle variation of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation. Copyright © 2023, The Authors. All rights reserved.

关键词： Active Galactic Nuclei

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Temperature-induced Lifshitz transition and possible excitonic instability in ZrSiSe

arXiv

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arXiv 2020年

作者： Chen, F.C. Fei, Y. Li, S.J. Wang, Q. Luo, X. Yan, J. Lu, W.J. Tong, P. Song, W.H. Zhu, X.B. Zhang, L. Zhou, H.B. Zheng, F.W. Zhang, P. Lichtenstein, A.L. Katsnelson, M.I. Yin, Y. Hao, Ning Sun, Y.P. Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Department of Physics Zhejiang University Hangzhou310027 China Institute of Applied Physics and Computational Mathematics Beijing100088 China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory HFIPS Chinese Academy of Sciences Hefei230031 China College of Mathematics and Physics Beijing University of Chemical Technology Beijing100029 China School of Physics and Physical Engineering Qufu Normal University Qufu273165 China Institute for Theoretical Physics University Hamburg Jungiusstrasse 9 HamburgD-20355 Germany Theoretical Physics and Applied Mathematics Department Ural Federal University Mira Street 19 Ekaterinburg620002 Russia Institute for Molecules and Materials Radboud University Heijendaalseweg 135 NijmegenNL-6525AJ Netherlands Collaborative Innovation Center of Microstructures Nanjing University Nanjing210093 China

The nodal-line semimetals have attracted immense interest due to the unique electronic structures such as the linear dispersion and the vanishing density of states as the Fermi energy approaching the nodes. Here, we report temperature-dependent transport and scanning tunneling microscopy(spectroscopy)[STM(S)] measurements on nodal-line semimetal ZrSiSe. Our experimental results and theoretical analyses consistently demonstrate that the temperature induces Lifshitz transitions at 80 K and 106 K in ZrSiSe, which results in the transport anomalies at the same temperatures. More strikingly, we observe a V-shape dip structure around Fermi energy from the STS spectrum at low temperature, which can be attributed to co-effect of the spin-orbit coupling and excitonic instability. Our observations indicate the correlation interaction may play an important role in ZrSiSe, which owns the quasi-two-dimensional electronic structures. Copyright © 2020, The Authors. All rights reserved.

关键词： Selenium compounds

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Thermoelectric Performance in Triplet-Ground-State Polymer Intrinsically Boosted by Enhanced Proquinoidal Characteristic

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Angewandte Chemie 2024年第1期137卷

作者： Runshi Wu Yu Wei Dr. Xiaojuan Dai Dr. Liqin Yan Dr. Wuyue Liu Prof. Dr. Dafei Yuan Prof. Dr. Jia Zhu Prof. Dr. Xiaozhang Zhu Beijing National Laboratory for Molecular Sciences CAS Key Laboratory for Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China School of Chemical Sciences University of Chinese Academy of Sciences Beijing 100049 China These authors contributed equally to this work College of Chemistry Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education Beijing Normal University Beijing 100190 China Laboratory of Theoretical and Computational Nanoscience CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Chinese Academy of Sciences Beijing 100190 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100190 China College of Materials Science and Engineering Hunan University Changsha Hunan 410082 China

Over the past decade, polymer thermoelectric materials featuring flexibility, lightness, and bio-friendliness have been paid increasing attention as promising candidates for waste heat recovery and energy generation. For a long time, the dominant approach to optimizing the thermoelectric performance of most organic materials is chemical doping, which, however, is not always ideal for practical applications due to its tendency to involve intricate processing procedure and trigger material and device instability. Currently, the pursuit of single-component neutral thermoelectric materials without exogenous doping presents a compelling alternative. In this work, we designed and synthesized a high-spin polymer material, PBBT-TT, by simultaneously employing thieno[3,4- b ]thiophene (T b T) and benzo[1,2- c : 4,5- c ′]bis[1,2,5]thiadiazole (BBT) units with pronounced proquinoidal characteristics, its analogue, PBBT-T to demonstrate the effect of the T b T unit was also synthesized. The results indicate that because of the enhanced quinoidal resonance, increased spin density and strong intermolecular antiferromagnetic coupling, PBBT-TT exhibits high intrinsic electrical conductivity and Seebeck coefficient, which showcases an outstanding power factor of 26.1 μW m −1 K −2 without doping. This achievement surpasses other neutral organic conjugated polymer and radical conductors, and is even comparable to some typical early-stage doped polymers. Notably, PBBT-TT exhibits remarkable ambient stability, retaining its initial thermoelectric performance over a 120-day period. Our finding demonstrates that modulating the intermolecular spin interactions in open-shell polymers through the introduction of strong proquinoidal units is an effective strategy for the development of doping-free, intrinsically high-performance polymer thermoelectric materials.

关键词： thermoelectric material conducting polymer diradicaloid quinoidal resonance doping-free

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Ni3+-induced semiconductor-to-metal transition in spinel nickel cobaltite thin films

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physical Review B 2021年第12期104卷 125136-125136页

作者： X. C. Huang W.-W. Li S. Zhang F. E. Oropeza G. Gorni V. A. de la Peña-O’Shea T.-L. Lee M. Wu L.-S. Wang D.-C. Qi L. Qiao J. Cheng K. H. L. Zhang State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 People's Republic of China MIIT Key Laboratory of Aerospace Information Materials and Physics College of Science Nanjing University of Aeronautics and Astronautics Nanjing 211106 People's Republic of China School of Physics University of Electronic Science and Technology of China Chengdu 610054 People's Republic of China Photoactivated Processes Unit IMDEA Energy Institute Parque Tecnológico de Móstoles Avda. Ramón de la Sagra 3 28935 Móstoles Madrid Spain CELLS-ALBA Synchrotron Carrer de la Llum 2-26 08290 Cerdanyola del Vallès Spain Diamond Light Source Ltd. Harwell Science and Innovation Campus Didcot OX11 0DE United Kingdom Department of Physics Xiamen University Xiamen 361005 People's Republic of China Fujian Key Laboratory of Materials Genome College of Materials Xiamen University Xiamen 361005 People's Republic of China School of Chemistry Physics and Mechanical Engineering Queensland University of Technology Brisbane Queensland 4001 Australia

In this paper, we report insights into the local atomic and electronic structure of NiCo2O4 epitaxial thin films and its correlation with electrical, optical, and magnetic properties. We grew structurally well-defined NiCo2O4 epitaxial thin films with controlled properties on MgAl2O4(001) substrates using pulsed laser deposition. Films grown at low temperatures (<400∘C) exhibit a ferrimagnetic and metallic behavior, while those grown at high temperatures are nonmagnetic semiconductors. The electronic structure and cation local atomic coordination of the respective films were investigated using a combination of resonant photoemission spectroscopy, x-ray absorption spectroscopy, and ab initio calculations. Our results unambiguously reveal that the Ni3+ valence state promoted at low growth temperature introduces delocalized Ni3d-derived states at the Fermi level (EF), responsible for the metallic state in NiCo2O4, while the Co3d-related state is more localized at higher binding energy. In the semiconducting films, the valence state of Ni is lowered and ∼+2. Further structural and defect chemistry studies indicate that the formation of oxygen vacancies and secondary CoO phases at high growth temperature are responsible for the Ni2+ valence state in NiCo2O4. The Ni3d-related state becomes localized away from EF, opening a band gap for a semiconducting state. The band gap of the semiconducting NiCo2O4 is estimated to be <0.8eV, which is much smaller than the quoted values in the literature ranging from 1.1 to 2.58 eV. Despite the small band gap, its optical transition is d−d dipole forbidden, and therefore, the semiconducting NiCo2O4 still shows reasonable transparency in the infrared-visible light region. The present insights into the role of Ni3+ in determining the electronic structure and defect chemistry of NiCo2O4 provide important guidance for use of NiCo2O4 in electrocatalysis and opto-electronics.

关键词： Density of states Electrical conductivity Electronic structure Cobaltates Spinels Thin films Transparent conducting oxides Density functional theory Epitaxy Laser ablation Resistivity measurements X-ray absorption spectroscopy X-ray photoelectron spectroscopy

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Design of Hollow Nanoreactors for Size- and Shape-Selective Catalytic Semihydrogenation Driven by Molecular Recognition

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Angewandte Chemie 2023年第43期135卷

作者： Yutong Pi Linxia Cui Prof. Wenhao Luo Dr. Haitao Li Dr. Yanfu Ma Dr. Na Ta Xinyao Wang Prof. Rui Gao Prof. Dan Wang Prof. Qihua Yang Prof. Jian Liu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road 116023 Dalian China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences 100049 Beijing China School of Chemistry and Chemical Engineering Inner Mongolia University 235 West University Street 010021 Hohhot China State Key Laboratory of Biochemical Engineering Key Laboratory of Science and Technology on Particle Materials Institute of Process Engineering Chinese Academy of Sciences 100190 Beijing China China University of Chinese Academy of Sciences 100049 Beijing China Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces Institute of Physical Chemistry Zhejiang Normal University 321004 Jinhua China DICP-Surrey Joint Centre for Future Materials Department of Chemical and Process Engineering University of Surrey GU2 7XH Guildford Surrey UK

Mimicking the structures and functions of cells to create artificial organelles has spurred the development of efficient strategies for production of hollow nanoreactors with biomimetic catalytic functions. However, such structure are challenging to fabricate and are thus rarely reported. We report the design of hollow nanoreactors with hollow multishelled structure (HoMS) and spatially loaded metal nanoparticles. Starting from a molecular-level design strategy, well-defined hollow multishelled structure phenolic resins (HoMS-PR) and carbon (HoMS-C) submicron particles were accurately constructed. HoMS-C serves as an excellent, versatile platform, owing to its tunable properties with tailored functional sites for achieving precise spatial location of metal nanoparticles, internally encapsulated (Pd@HoMS-C) or externally supported (Pd/HoMS-C). Impressively, the combination of the delicate nanoarchitecture and spatially loaded metal nanoparticles endow the pair of nanoreactors with size–shape-selective molecular recognition properties in catalytic semihydrogenation, including high activity and selectivity of Pd@HoMS-C for small aliphatic substrates and Pd/HoMS-C for large aromatic substrates. Theoretical calculations provide insight into the pair of nanoreactors with distinct behaviors due to the differences in energy barrier of substrate adsorption. This work provides guidance on the rational design and accurate construction of hollow nanoreactors with precisely located active sites and a finely modulated microenvironment by mimicking the functions of cells.

关键词： Hollow Structure Hydrogenation Nanoreactor Polymer Supported Catalyst

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