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arXiv 2024年

作者： Elenewski, Justin E. Camara, Christina M. Kalev, Amir MIT Lincoln Laboratory LexingtonMA02421 United States Department of Pediatric Oncology The Linde Program in Cancer Chemical Biology Dana–Farber Cancer Institute BostonMA United States Information Sciences Institute University of Southern California ArlingtonVA22203 United States Department of Physics and Astronomy Center for Quantum Information Science & Technology University of Southern California Los AngelesCA90089 United States

Nuclear magnetic resonance spectroscopy is a prominent analytical tool, with applications throughout chemistry, medicine and solid–state physics. While conventional NMR spectrometers require large magnetic fields to interrogate a sample, recent advances in atomic magnetometry have enabled this spectroscopy far below geomagnetic field strengths. This zero–to–ultralow (ZULF) field regime can be advantageous since it mitigates relaxation and reveals spin couplings that are otherwise obscured, all while using compact and lower–overhead instrumentation. The resulting spectra are nonetheless difficult to interpret without computation, which can be taxing due to the presence of vector couplings and long–range spin networks. Following recent proposals, we demonstrate how fault–tolerant quantum computation could be used to simulate these spectra. Our analysis spans from input selection to the construction of explicit circuits based on qubitized quantum dynamics. By maintaining parity with experimental requirements, we demonstrate how NMR spectral prediction might be an early application for fault–tolerant quantum computers. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum computers

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First results of pulsar observations with the LST-1 38

First results of pulsar observations with the LST-1

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38th International Cosmic Ray Conference, ICRC 2023

作者： Mas-Aguilar, Álvaro Brunelli, Giulia Ceribella, Giovanni López-Moya, Marcos López-Coto, Rubén Abe, K. Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Brunelli, G. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Hütten, M. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. IPARCOS Department of EMFTEL Universidad Complutense de Madrid MadridE-28040 Spain INAF-OAS Università di Bologna Bologna40129 Italy Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Max-Planck-Institut for Physics Munich80805 Germany Department of Physics Tokai University Japan Institute for Cosmic Ray Research University of Tokyo Japan Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Spain INAF Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy Max-Planck-Institut für Physik Germany INFN Sezione di Padova Università degli Studi di Padova Italy The Barcelona Institute of Science and Technology Spain LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain CIEMAT Spain Department of Physics TU Dortmund University Germany INFN Sezione di Bari Politecnico di Bari Italy INAF Osservatorio Astronomico di Brera Italy INFN Sezione di Trieste Università degli Studi di Udine Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Italy Aix Marseille Univ CNRS IN2P3 CPPM France INFN Sezione di Bari Università di Bari Italy INFN Sezione di Torino Italy Palacky University Olomouc Faculty of Science Czech Republic University of Alcalá UAH Spain Port d’Informació Científica Spain University of Rijeka Department of Physics Croatia Institute for Theoretical Physics and Astrophysics Universität Würzburg Germany Institut für Theoretische Physik Lehrstuhl IV: Plasma-Astroteilchenphysik Ruhr-Universität B

After the discovery of Crab, Vela, and Geminga pulsars at Very High Energies, the search for new pulsars at tens of GeV has been gaining huge importance. However, their steep spectra along with the sensitivity of the current generation of Imaging Atmospheric Cherenkov telescopes (IACTs) are limiting the capability to detect more pulsars. The LST-1 is the first prototype of the Large-Sized Telescope of the forthcoming CTA observatory with enhanced sensitivity at tens of GeV. The LST-1 started its commissioning phase in 2018, and since then it has observed the Crab pulsar regularly. Here, we show the first results of the analysis of the Crab and other pulsars taken with the LST-1. The two characteristic emission peaks of the Crab pulsar, P1, and P2, are detected with high significance showing a clear improvement in sensitivity over the previous generation of IACTs. The spectrum is reconstructed up to 450 GeV for P1 and up to 700 GeV for P2. The low energy threshold of LST-1 also allows us to measure the spectrum of the Crab pulsar in the overlapping region with the Fermi-LAT and cross-calibrate both instruments. The results obtained with the first pulsar observations with the LST-1 confirm the excellent potential of LST telescopes to study and discover new pulsars in the near future. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Shellfish

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Artificial intelligence for geoscience:Progress,challenges,and perspectives

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The Innovation 2024年第5期5卷 136-160,135页

作者： Tianjie Zhao Sheng Wang Chaojun Ouyang Min Chen Chenying Liu Jin Zhang Long Yu Fei Wang Yong Xie Jun Li Fang Wang Sabine Grunwald Bryan MWong Fan Zhang Zhen Qian Yongjun Xu Chengqing Yu Wei Han Tao Sun Zezhi Shao Tangwen Qian Zhao Chen Jiangyuan Zeng Huai Zhang Husi Letu Bing Zhang Li Wang Lei Luo Chong Shi Hongjun Su Hongsheng Zhang Shuai Yin Ni Huang Wei Zhao Nan Li Chaolei Zheng Yang Zhou Changping Huang Defeng Feng Qingsong Xu Yan Wu Danfeng Hong Zhenyu Wang Yinyi Lin Tangtang Zhang Prashant Kumar Antonio Plaza Jocelyn Chanussot Jiabao Zhang Jiancheng Shi Lizhe Wang Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Computer Science China University of GeosciencesWuhan 430078China State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Key Laboratory of Virtual Geographic Environment(Ministry of Education of PRC) Nanjing Normal UniversityNanjing 210023China Data Science in Earth Observation Technical University of Munich80333 MunichGermany The National Key Laboratory of Water Disaster Prevention Yangtze Institute for Conservation and DevelopmentHohai UniversityNanjing 210098China Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Soil Water and Ecosystem Sciences DepartmentUniversity of FloridaPO Box 110290GainesvilleFLUSA Materials Science Engineering Program Cooperating Faculty Member in the Department of Chemistry and Department of Physics Astronomy University of CaliforniaCaliforniaRiversideCA 92521USA Institute of Remote Sensing and Geographical Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China College of Geography and Remote Sensing Hohai UniversityNanjing 211100China Department of Geography The University of Hong KongHong Kong 999077SARChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing 210044China School of Environmental Science and Engineering Nanjing University of Information Science&TechnologyNanjing 210044China Collaborative Inno

This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intelligence(AI)and data collection *** models,which are grounded in physical and numerical frameworks,provide robust explanations by explicitly reconstructing underlying physical ***,their limitations in comprehensively capturing Earth’s complexities and uncertainties pose challenges in optimization and real-world *** contrast,contemporary data-driven models,particularly those utilizing machine learning(ML)and deep learning(DL),leverage extensive geoscience data to glean insights without requiring exhaustive theoretical *** techniques have shown promise in addressing Earth science-related ***,challenges such as data scarcity,computational demands,data privacy concerns,and the“black-box”nature of AI models hinder their seamless integration into *** integration of physics-based and data-driven methodologies into hybrid models presents an alternative *** models,which incorporate domain knowledge to guide AI methodologies,demonstrate enhanced efficiency and performance with reduced training data *** review provides a comprehensive overview of geoscientific research paradigms,emphasizing untapped opportunities at the intersection of advanced AI techniques and *** examines major methodologies,showcases advances in large-scale models,and discusses the challenges and prospects that will shape the future landscape of AI in *** paper outlines a dynamic field ripe with possibilities,poised to unlock new understandings of Earth’s complexities and further advance geoscience exploration.

关键词： Earth utilizing landscape

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Galactic Center Studies with CTA-LST-1 38

Galactic Center Studies with CTA-LST-1

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38th International Cosmic Ray Conference, ICRC 2023

作者： Abe, Shotaro Ohtani, Yoshiki Strzys, Marcel Teshima, Masahiro Vovk, Ievgen Abe, K. Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Hütten, M. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Le Flour, T. Linhoff, M. Longo, F. López-Coto, R. Institute for Cosmic Ray Research Kashiwa-no-ha 5-1-5 Kashiwa-shi Chiba Japan Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany Department of Physics Tokai University Japan Institute for Cosmic Ray Research University of Tokyo Japan Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Spain Instituto de Astrofísica de Andalucía-CSIC Spain EMFTEL department IPARCOS Universidad Complutense de Madrid Spain INAF Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy INFN Sezione di Padova Università degli Studi di Padova Italy The Barcelona Institute of Science and Technology Spain LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain CIEMAT Spain Department of Physics TU Dortmund University Germany INFN Sezione di Bari Politecnico di Bari Italy INAF Osservatorio Astronomico di Brera Italy INFN Sezione di Trieste Università degli Studi di Udine Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Italy Aix Marseille Univ CNRS IN2P3 CPPM France INFN Sezione di Bari Università di Bari Italy INFN Sezione di Torino Italy Palacky University Olomouc Faculty of Science Czech Republic University of Alcalá UAH Spain Port d’Informació Científica Spain University of Rijeka Department of Physics Croatia Institute for Theoretical Physics and Astrophysics Universität Würzburg Germany Institut für Theoretische Physik Lehrstuhl IV: Plasma-Astroteilchenphysik Ruhr-Universität Bochum Germany INFN Sezione di Roma La Sapienza Italy ILAN

The Galactic Center region is known to host a wide variety of very-high-energy gamma-ray sources. In 2018 the prototype of the Large-Sized Telescope (LST-1) for CTA was inaugurated, and has been regularly observing the Galactic Center since 2021. To observe the Galactic Center in the southern sky, LST-1, located in the Northern hemisphere, requires an observation mode at a low telescope elevation. In this study, we assessed the performance of LST-1 at the large zenith angle, based both on simulations and observational data for the standard candle Crab Nebula. Analyzing LST-1 data from the Galactic Center observations, we obtained the spectral energy distributions of Sagittarius A* and G0.9+0.1, which were comparable with the results from the current imaging atmospheric Cherenkov telescopes, with a broad energy coverage owing to the large-zenith-angle observation and the low energy threshold of LST-1. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Galaxies

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Room-temperature intrinsic ferromagnetism of two-dimensional Na2Cl crystals originated by s- and p-orbitals

arXiv

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arXiv 2024年

作者： Zhao, Yimin Li, Yunzhang Chen, Liang Zhang, Quan Liu, Xing Yang, Yizhou Yi, Ruobing Zhang, Lihao He, Zhenglin Qiu, Yinwei Nie, Dexi Tian, Fanghua Wang, Zhe Yang, Zhiwei Zhang, Lei Shi, Guosheng Zhang, Shengli Fang, Haiping MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiaotong University Xi'An710049 China Shanghai Applied Radiation Institute Shanghai University Shanghai200444 China School of Physical Science and Technology Ningbo University Ningbo315211 China Department of Optical Engineering Zhejiang Prov Key Lab Carbon Cycling Forest Ecosy Zhejiang Prov Key Lab of Chemical Utilization of Forestry Biomass Zhejiang A&F University Lin'An311300 China School of Science East China University of Science and Technology Shanghai200237 China

Ferromagnetism, as one of the most valuable properties of materials, has attracted sustained and widespread interest in basic and applied research from ancient compasses to modern electronic devices1-7. Traditionally, intrinsic ferromagnetism has been attributed to the permanent magnetic moment induced by partially filled d- or f-orbitals8. However, the development of ferromagnetic materials has been limited by this electronic structure convention. Thus, the identification of additional materials that are not constrained by this conventional rule but also exhibit intrinsic ferromagnetism is highly expected and may impact all the fields based on ferromagnetism. Here, we report the direct observation of room-temperature intrinsic ferromagnetism in two-dimensional (2D) Na2Cl crystals, in which there are only partially filled s- and p-orbitals rather than d- or f-orbitals, using the superconducting quantum interference device (SQUID) and magnetic force microscope (MFM). These Na2Cl crystals formed in reduced graphene oxide (rGO) membranes have an unconventional stoichiometric structure leading to unique electron and spin distributions. And the structure of these 2D Na2Cl crystals, including the Na and Cl sites, is characterized in situ for the first time and directly observed by cryo-electron microscopy (cryo-EM) based on the observed difference in contrast between Na stacked with Cl and single Na. These findings break the conventional rule of intrinsic ferromagnetism and provide new insights into the design of novel magnetic and electronic devices and transistors with a size down to the atomic scale. Copyright © 2024, The Authors. All rights reserved.

关键词： Ferromagnetism

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Substitution of Lead with Tin Suppresses Ionic Transport in Halide Perovskite Optoelectronics

arXiv

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arXiv 2023年

作者： Dey, Krishanu Ghosh, Dibyajyoti Pilot, Matthew Pering, Samuel R. Roose, Bart Deswal, Priyanka Senanayak, Satyaprasad P. Cameron, Petra J. Islam, M. Saiful Stranks, Samuel D. Cavendish Laboratory University of Cambridge Cambridge United Kingdom Department of Materials Science and Engineering Department of Chemistry Indian Institute of Technology Hauz Khas Delhi India Department of Chemistry University of Bath Bath United Kingdom Department of Materials Loughborough University Loughborough United Kingdom Department of Chemical Engineering and Biotechnology University of Cambridge Cambridge United Kingdom Department of Physics Indian Institute of Technology Hauz Khas Delhi India Nanoelectronics and Device Physics Lab National Institute of Science Education and Research School of Physical Sciences HBNI Jatni India Department of Materials University of Oxford Oxford United Kingdom

Despite the rapid rise in the performance of a variety of perovskite optoelectronic devices with vertical charge transport, the effects of ion migration remain a common and longstanding Achilles’ heel limiting the long-term operational stability of lead halide perovskite devices. However, there is still limited understanding of the impact of tin (Sn) substitution on the ion dynamics of lead (Pb) halide perovskites. Here, we employ scan-rate-dependent current-voltage measurements on Pb and mixed Pb-Sn perovskite solar cells to show that short circuit current losses at lower scan rates, which can be traced to the presence of mobile ions, are present in both kinds of perovskites. To understand the kinetics of ion migration, we carry out scan-rate-dependent hysteresis analyses and temperature-dependent impedance spectroscopy measurements, which demonstrate suppressed ion migration in Pb-Sn devices compared to their Pb-only analogues. By linking these experimental observations to first-principles calculations on mixed Pb-Sn perovskites, we reveal the key role played by Sn vacancies in increasing the iodide ion migration barrier due to local structural distortions. These results highlight the beneficial effect of Sn substitution in mitigating undesirable ion migration in halide perovskites, with potential implications for future device development. © 2023, CC BY.

关键词： Perovskite

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Reshaped Weyl fermionic dispersions driven by Coulomb interactions in MoTe2

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physical Review B 2022年第4期105卷 045143-045143页

作者： Seoung-Hun Kang Sangjun Jeon Hyun-Jung Kim Wonhee Ko Suyeon Cho Se Hwang Kang Sung Wng Kim Heejun Yang Hyo Won Kim Young-Woo Son Korea Institute for Advanced Study Seoul 02455 Korea Department of Physics Chung-Ang University Seoul 06974 Korea Peter Grünberg Institut and Institute for Advanced Simulation Forschungszentrum Jülich and JARA D-52425 Jülich Germany Samsung Advanced Institute of Technology Suwon 16678 Korea Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Chemical Engineering and Materials Science Graduate Program in System Health Science and Engineering Ewha Womans University Seoul 03760 Korea Department of Energy Science Sungkyunkwan University Suwon 16419 Korea Department of Physics Korea Advanced Institute of Science and Technology Daejeon 34141 Korea

We report the direct evidence of impacts of the Coulomb interaction in a prototypical Weyl semimetal, MoTe2, that alter its bare bands in a wide range of energy and momentum. Our quasiparticle interference patterns measured using scanning tunneling microscopy are shown to match the joint density of states of quasiparticle energy bands including momentum-dependent self-energy corrections, while electronic energy bands based on the other simpler local approximations of the Coulomb interaction fail to explain neither the correct number of quasiparticle pockets nor the shape of their dispersions observed in our spectrum. With this, we predict a transition between type-I and type-II Weyl fermions with doping and resolve its disparate quantum oscillation experiments, thus highlighting the critical roles of Coulomb interactions in layered Weyl semimetals.

关键词： Electronic structure First-principles calculations Quasiparticles & collective excitations Topological materials Weyl fermions Scanning electron microscopy Scanning tunneling spectroscopy

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Optimizing the Resistivity of Colloidal Sno2 Thin Films by Ion Implantation and Annealing

SSRN

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SSRN 2024年

作者： Yusuf, Abubakar Sadiq Markwitz, Martin Chen, Zhan Ramezani, Maziar Kennedy, John V. Fiedler, Holger School of Engineering Computer and Mathematical Sciences Auckland University of Technology PO Box 92006 Auckland1142 New Zealand National Isotope Centre GNS Science PO Box 30368 Lower Hutt5010 New Zealand School of Physical Sciences Department of Physics Federal University of Technology PMB 65 Niger State Minna Nigeria School of Chemical and Physical Sciences Victoria University of Wellington PO Box 600 Wellington6140 New Zealand The MacDiarmid Institute for Advanced Materials and Nanotechnology Victoria University of Wellington PO Box 600 Wellington6140 New Zealand

Tin oxide (SnO2) is a critical material for a wide range of applications, such as in perovskite solar cells, gas sensors as well as for photocatalysis. For these applications the transparency to visible light, high availability, cheap fabrication process and high conductivity of SnO2 benefits commercial deployment. In this paper, we demonstrate that the resistivity of widely colloidal SnO2 can be reduced by noble gas ion beam modification. After low energy implantation with a fluence of 4 ×1015 ***-2 at 25 keV and annealing 200˚C in open air, the resistivity of as-deposited film was (178.2 ± 6.1) μΩcm reduced to (133.2 ± 5.2) μΩcm, a reduction of 25%. Hall effect measurements showed that the primary cause of this is the increase in carrier concentration from (8.1 ± 0.3) × 1020 cm-3 to (9.9 ± 0.3) × 1020 cm-3. Annealing at 200˚C resulted in the removal of defect clusters introduced by implantation, while annealing at 300˚C resulted in the oxidation of the films, increasing their resistivity. The concentration of oxygen vacancy defects can be controlled by a combination of low energy noble gas ion implantation and annealing, providing promising performance increases for potential applications of SnO2 where a low resistivity is crucial. © 2024, The Authors. All rights reserved.

关键词： Perovskite

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Electronic ratchet effect in a moiré system: signatures of excitonic ferroelectricity

arXiv

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arXiv 2023年

作者： Zheng, Zhiren Wang, Xueqiao Zhu, Ziyan Carr, Stephen Devakul, Trithep de la Barrera, Sergio Paul, Nisarga Huang, Zumeng Gao, Anyuan Zhang, Yang Bérubé, Damien Evancho, Kathryn Natasha Watanabe, Kenji Taniguchi, Takashi Fu, Liang Wang, Yao Xu, Su-Yang Kaxiras, Efthimios Jarillo-Herrero, Pablo Ma, Qiong Department of Physics Massachusetts Institute of Technology CambridgeMA United States Stanford Institute of Materials and Energy Science SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Brown Theoretical Physics Center Department of Physics Brown University ProvidenceRI United States Department of Physics Boston College Chestnut HillMA United States Department of Chemistry and Chemical Biology Harvard University CambridgeMA United States Department of Physics and Astronomy Clemson University ClemsonSC United States Research Center for Functional Materials National Institute for Materials Science Tsukuba Japan International Center for Material Nanoarchitectonics National Institute for Materials Science Tsukuba Japan Department of Physics Harvard University CambridgeMA United States CIFAR Azrieli Global Scholars program CIFAR Toronto Canada

Electronic ferroelectricity represents a new paradigm where spontaneous symmetry breaking driven by electronic correlations, in contrast to traditional lattice-driven ferroelectricity, leads to the formation of electric dipoles. Despite the potential application advantages arising from its electronic nature, switchable electronic ferroelectricity remains exceedingly rare. Here, we report the discovery of an electronic ratchet effect that manifests itself as switchable electronic ferroelectricity in a layer-contrasting graphene-boron nitride moiré heterostructure. Our engineered layer-asymmetric moiré potential landscapes result in layer-polarized localized and itinerant electronic subsystems. At particular fillings of the localized subsystem, we find a ratcheting injection of itinerant carriers in a non-volatile manner, leading to a highly unusual ferroelectric response. Strikingly, the remnant polarization can be stabilized at multiple (quasi-continuous) states with behavior markedly distinct from known ferroelectrics. Our experimental observations, simulations, and theoretical analysis suggest that dipolar excitons are the driving force and elementary ferroelectric units in our system. This signifies a new type of electronic ferroelectricity where the formation of dipolar excitons with aligned moments generates a macroscopic polarization and leads to an electronically-driven ferroelectric response, which we term excitonic ferroelectricity. Such new ferroelectrics, driven by quantum objects like dipolar excitons, could pave the way to innovative quantum analog memory and synaptic devices. Copyright © 2023, The Authors. All rights reserved.

关键词： Ferroelectricity

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Effect of size and crystalline phase of TiO2 nanotubes on cell behaviors: A high throughput study using gradient TiO2 nanotubes

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Bioactive Materials 2020年第4期5卷 1062-1070页

作者： Yanran Li Si Wang Yuanjun Dong Ping Mu Yun Yang Xiangyang Liu Changjian Lin Qiaoling Huang Research Institute for Biomimetics and Soft Matter Fujian Provincial Key Laboratory for Soft Functional Materials ResearchDepartment of PhysicsCollege of Physical Science and TechnologyXiamen UniversityXiamen361005China Department of Physics National University of Singapore2 Science Drive 3117542Singapore State Key Laboratory for Physical Chemistry of Solid Surfaces Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China

The research of TiO2 nanotubes(TNTs)in the field of biomedicine has been increasingly ***,given the diversity of the nanoscale dimension and controversial reports,our understanding of the structure-property relationships of TNTs is not yet *** this paper,gradient TNTs with a wide diameter range of 20-350 nm were achieved by bipolar electrochemistry and utilized for a thorough high-throughput study of the effect of nanotube dimension and crystalline phase on protein adsorption and cell *** indicated that protein adsorption escalated with nanotube dimension whereas cell proliferation and differentiation are preferred on small diameter(<70 nm)*** diameter anatase nanotubes had higher adsorption of serum proteins than as-prepared *** only as-prepared small diameter nanotubes presented slightly higher cell proliferation than corresponding annealed nanotubes whereas there was no discernible difference between as-prepared and annealed nanotubes on cell differentiation for the entire *** findings replenish previous research about how cell responses to TNTs with a wide diameter range and provide scientific guidance for the optimal design of biomedical materials.

关键词： Gradient TiO2 nanotubes High-throughput screening Protein adsorption Cell proliferation Cell differentiation

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