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Processing-dependent thermal stability of a prototypical amorphous metal oxide

Physical Review Materials 2018年第5期2卷 053401-053401页

作者： Li Zeng Mahyar M. Moghadam D. Bruce Buchholz Ran Li Denis T. Keane Vinayak P. Dravid Robert P. H. Chang Peter W. Voorhees Tobin J. Marks Michael J. Bedzyk Graduate Program in Applied Physics Northwestern University Evanston Illinois 60208 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Northwestern Synchrotron Research Center Argonne Illinois 60439 USA Department of Chemistry Northwestern University Evanston Illinois 60208 USA Department of Physics and Astronomy Northwestern University Evanston Illinois 60208 USA

Amorphous metal oxides (AMOs) are important candidate materials for fabricating next-generation thin-film transistors. While much attention has been directed toward the synthesis and electrical properties of AMOs, less is known about growth conditions that allow AMOs to retain their desirable amorphous state when subjected to high operating temperatures. Using in situ x-ray scattering and level-set simulations, we explore the time evolution of the crystallization process for a set of amorphous In2O3 thin films synthesized by pulsed-laser deposition at deposition temperatures (Td) of −50, −25, and 0 °C. The films were annealed isothermally and the degree of crystallinity was determined by a quantitative analysis of the time-evolved x-ray scattering patterns. As expected, for films grown at the same Td, an increase in the annealing temperature TA led to a shorter delay prior to the onset of crystallization, and a faster crystallization rate. Moreover, when lowering the deposition temperature by 25 °C, a 40 °C increase in annealing temperature is needed to achieve the same time interval for the crystals to grow from 10 to 90% volume fraction of the sample. Films grown at Td=0∘C exhibited strong cubic texture after crystallization. A level-set method was employed to quantitatively model the texture that develops in the microstructures and to determine key parameters, such as the interface growth velocity, the nucleation density, and the activation energy. The differences observed in the crystallization processes are attributed to the changes in the atomic structure of the oxide and possible nanocrystalline inclusions that formed during the deposition of the amorphous phase.

关键词： Annealing Crystallization Electron diffraction Laser ablation Numerical techniques X-ray diffraction

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A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations

arXiv

引用

arXiv 2022年

作者： Acciari, V.A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Engels, A. Arbet Artero, M. Asano, K. Baack, D. Babić, A. Baquero, A. de Almeida, U. Barres Barrio, J.A. Batković, I. González, J. Becerra Bednarek, W. Bernardini, E. Bernardos, M. Berti, A. Besenrieder, J. Bhattacharyya, W. Bigongiari, C. Biland, A. Blanch, O. Bökenkamp, H. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Carosi, R. Ceribella, G. Cerruti, M. Chai, Y. Chilingarian, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Amico, G. D’Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. Del Popolo, A. Delfino, M. Delgado, J. Mendez, C. Delgado Depaoli, D. Di Pierro, F. Di Venere, L. Espiñeira, E. Do Souto Prester, D. Dominis Donini, A. Dorner, D. Doro, M. Elsaesser, D. Ramazani, V. Fallah Fariña, L. Fattorini, A. Font, L. Fruck, C. Fukami, S. Fukazawa, Y. López, R.J. García Garczarczyk, M. Gasparyan, S. Gaug, M. Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Green, J.G. Green, D. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Inada, T. Iotov, R. Ishio, K. Iwamura, Y. Martínez, I. Jiménez Jormanainen, J. Jouvin, L. Kerszberg, D. Kobayashi, Y. Kubo, H. Kushida, J. Lamastra, A. Lelas, D. Leone, F. Lindfors, E. Linhoff, L. Liodakis, I. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. de Oliveira Fraga, B. Machado Maggio, C. Majumdar, P. Makariev, M. Mallamaci, M. Maneva, G. Manganaro, M. Mannheim, K. Mariotti, M. Martínez, M. Aguilar, A. Mas Mazin, D. Menchiari, S. Mender, S. Mićanović, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. Molina, E. Mondal, H.A. Moralejo, A. Morcuende, D. Moreno, V. Moretti, E. Nakamori, T. Nanci, C. Nava, L. Neustroev, V. Rosillo, M. Nievas Nigro, C. Nilsson, K. Nishijima, K. Noda, K. Nozaki, S. Ohtani, Y. Oka, T. Otero-Santos, J. Paiano, S. Palatiello, M. Paneque, D. Paoletti, R. Paredes, J.M. Pavletić, L. Peñil, P. Persic, M. Pihet, M. Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna La Laguna TenerifeE-38200 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Bellaterra BarcelonaE-08193 Spain The University of Tokyo Chiba Kashiwa277-8582 Japan Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil Università di Padova INFN PadovaI-35131 Italy University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland ZeuthenD-15738 Germany ETH Zürich ZürichCH-8093 Switzerland Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Armenian MAGIC Group A. Alikhanyan National Science Laboratory Yerevan0036 Armenia Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group INFN Sezione di Catania Dipartimento di Fisica e Astronomia University of Catania CataniaI-95123 Italy INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari BariI-70125 Italy Croatian MAGIC Group University of Rijeka Department of Physics Rijeka51000 Croatia Universität Würzburg WürzburgD-97074 Germany Finnish MAGIC Group Finnish Centre for Astronomy with ESO University of Turku TurkuFI-20014 Finland Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Japanese MAGIC Group: Physics Program Graduate School of Advanced Science and E

Context. Extended and delayed emission around distant TeV sources induced by the effects of propagation of γ rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). Aims. We search for delayed GeV emission from the hard-spectrum TeV γ-ray emitting blazar 1ES 0229+200, with the goal to detect or constrain the IGMF-dependent secondary flux generated during the propagation of TeV γ rays through the intergalactic medium. Methods. We analyze the most recent MAGIC observations over a 5 year time span, and complement them with historic data of the H.E.S.S. and VERITAS telescopes along with a 12-year long exposure of the Fermi/LAT telescope. We use them to trace source evolution in the GeV-TeV band over one-and-a-half decade in time. We use Monte Carlo simulations to predict the delayed secondary γ-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compare these predictions for various assumed IGMF strengths to all available measurements of the γ-ray flux evolution. Results. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14 years time span of observations. No evidence for the flux variability is found in 1 − 100 GeV energy range accessible to Fermi/LAT. Non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B > 1.8 × 10−17 G for long correlation length IGMF and B > 10−14 G for an IGMF of the cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields which might explain the baryon asymmetry of the Universe. Copyright © 2022, The Authors. All ri

关键词： Monte Carlo methods

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Demographics of black holes at g scales: accretion flows, jets, and shadows

arXiv

引用

arXiv 2024年

作者： Nair, Dhanya G. Nagar, Neil M. Ramakrishnan, Venkatessh Wielgus, Maciek Arratia, Vicente Krichbaum, Thomas P. Zhang, Xinyue A. Ricarte, Angelo Silpa, S. Hernández-Yévenes, Joaquín Ford, Nicole M. Bandyopadhyay, Bidisha Gurwell, Mark Burridge, Roman Pesce, Dominic W. Doeleman, Sheperd S. Kim, Jae-Young Kim, Daewon Janssen, Michael von Fellenberg, Sebastiano D. Fromm, Christian M. Lee, Deokhyeong Falcke, Heino Wagner, Jan Bower, Geoffrey C. Baczko, Anne-Kathrin Kim, Dong-Jin Akiyama, Kazunori Asada, Keiichi Arevalo, Patricia Bignall, Hayley Blackburn, Lindy Broderick, Avery E. Brunthaler, Andreas Chan, Chi-Kwan Doi, Akihiro Fish, Vincent L. Fomalont, Edward Gómez, José L. Haggard, Daryl Hada, Kazuhiro Herrera-Camus, Rodrigo Hoak, Daniel Hughes, David Hlavacek-Larrondo, Julie Jorstad, Svetlana Johnson, Michael D. Kawashima, Tomohisa Keating, Garrett K. Kharb, Preeti Koay, Jun Yi Koyama, Shoko Kuo, Cheng-Yu Leigh, Nathan W.C. Lira, Paulina Lindqvist, Michael Lobanov, Andrei P. Lo, Wen-Ping Lu, Ru-Sen Markoff, Sera MacDonald, Nicholas R. Martínez-Aldama, Mary Loli Matthews, Lynn D. Matsushita, Satoki Mezcua, Mar Moscibrodzka, Monika Müller, Hendrik Nagai, Hiroshi Nakamura, Masanori Natarajan, Priyamvada Narayanan, Gopal Nowak, Michael A. Olivares Sánchez, Héctor Raúl Park, Jongho Psaltis, Dimitrios Pu, Hung-Yi Porth, Oliver Rao, Ramprasad Reynolds, Cormac Reeves, Rodrigo Romero-Cañizales, Cristina Ros, Eduardo Rottmann, Helge Roy, Alan L. Schleicher, Dominik Savolainen, Tuomas Impellizzeri, C.M. Violette Treister, Ezequiel Wiik, Kaj Zensus, J. Anton Astronomy Department Universidad de Concepción Casilla 160-C Concepción Chile Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Finnish Centre for Astronomy with ESO University of Turku FI-20014 Finland Instituto de Astrofisica de Andalucia-CSIC Glorieta de la Astronomia s/n GranadaE-18008 Spain Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138 United States Department of Physics McGill University 3600 rue University MontréalQCH3A 2T8 Canada Massachusetts Institute of Technology Haystack Observatory 99 Millstone Road WestfordMA01886 United States Black Hole Initiative Harvard University 20 Garden Street CambridgeMA02138 United States National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-43992 Sweden Institute of Astronomy and Astrophysics Academia Sinica 645 N. A’ohoku Place HiloHI96720 United States Department of Physics and Astronomy University of Hawaii at Manoa 2505 Correa Road HonoluluHI96822 United States Perimeter Institute for Theoretical Physics 31 Caroline Street North WaterlooONN2L 2Y5 Canada Department of Physics and Astronomy University of Waterloo 200 University Avenue West WaterlooONN2L 3G1 Canada Waterloo Centre for Astrophysics University of Waterloo Waterloo Canada Steward Observatory Department of Astronomy University of Arizona 933 N. Cherry Ave. TucsonAZ85721 United States Data Science Institute University of Arizona 1230 N. Cherry Ave. TucsonAZ85721 United States Program in Applied Mathematics University of Arizona 617 N. Santa Rita TucsonAZ85721 United States Radboud University P.O. Box 9010 Nijmegen6500 GL Netherlands Institut für Theoretische Physik Goethe-Universität Frankfurt Max-von-Laue-Straße 1 Frankfurt am MainD-60438 Germany Institut für Theoretische Physik und Astrophysik Universität

Using the Event Horizon Telescope (EHT), the gravitationally lensed rings around the supermassive black holes (SMBHs) in Messier 87 (M87), which has billions of solar masses and a strong jet, and Sagittarius A* (Sgr A*), which has millions of solar masses and a weak or no jet, have now been successfully imaged at a resolution under 10 gravitational radii (Rg = GM/c2, where M is the SMBH mass). To expand studies beyond M87 and Sgr A*, we have constructed the ‘Event Horizon and Environs (ETHER)’ sample, a comprehensive database currently encompassing approximately 3.15 million SMBH mass estimates, ∼ 20,000 Very-Long Baseline Interferometry (VLBI) radio flux densities, and ∼ 36,000 hard X-ray flux densities. This database is designed to identify and optimize target selection for the EHT and its upgrades on the ground and in space. Within the ETHER database, we have identified a ‘Gold Sample’ (GS) of nearby low-luminosity Active Galactic Nuclei (AGNs) that are optimal for studying jet bases, and potentially imaging black hole shadows, with the EHT and its upgrades. We observed 27 of these AGNs using the EHT from 2022 to 2024, providing a unique opportunity to resolve and image accretion flows and jets at resolutions of ≤ 100 Rg. Only a few SMBHs have sufficiently high enough flux density to be imaged at scales of ≤ 50 Rgwith the present EHT. Among these are M87, Sgr A*, NGC 4594 (Sombrero/M104), NGC 4261, and NGC 4374 (Messier 84/M84). Of these, NGC 4261, Sombrero, and M84 have been observed and/or are scheduled for deep imaging with EHT+ALMA from 2023 to 2025. Sombrero, NGC 4261, M84, NGC 4278, and NGC 5232 are clearly detected in our EHT+ALMA observations in 2022, indicating that the 230 GHz flux density from the accretion flows is significantly high. Ongoing imaging of the ETHER GS will enable measurements of black hole mass and spin, help constrain General Relativity (GR), and enrich our understanding of jet launching and accretion inflows across a broad multi-param

关键词： Radiation flux density

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Signatures of electronic nematicity in (111) LaAlO3/SrTiO3 interfaces

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Physical Review B 2018年第4期97卷 041408(R)-041408(R)页

作者： S. Davis Z. Huang K. Han Ariando T. Venkatesan V. Chandrasekhar Graduate Program in Applied Physics and Department of Physics and Astronomy Northwestern University 2145 Sheridan Road Evanston Illinois 60208 USA NUSNNI-Nanocore National University of Singapore 117411 Singapore Department of Physics National University of Singapore 117551 Singapore NUS Graduate School for Integrative Sciences & Engineering National University of Singapore 117456 Singapore Department of Electrical and Computer Engineering National University of Singapore 117576 Singapore Department of Material Science and Engineering National University of Singapore 117575 Singapore

The two-dimensional conducting gas (2DCG) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has been widely studied due to the multitude of in situ tunable phenomena that exist at the interface. Recently it has been shown that nearly every property of the 2DEG that forms at the interface of (111) oriented LAO/STO is strongly anisotropic with respect to the in-plane crystal direction. This in-plane rotational symmetry breaking points to the existence of an electronic nematic phase at the interface that can be modified by an in situ electrostatic back-gate potential. Here we show that the onset temperature of the anisotropy in the longitudinal resistance is T≈22K, which does not match up with any known structural transition, and coincides with the onset of anisotropy in the Hall response of the system. Furthermore, below 22 K, charge transport is activated in nature with different activation energies along the two in-plane crystal directions. Such a response implies that the band edges along the two directions are different and provides further evidence of an electronic nematic state at the interface.

关键词： Electrical properties Hall effect Nematic order Transport phenomena Hall bar Resistivity measurements Transport techniques

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Performance of the joint LST-1 and MAGIC observations evaluated with Crab Nebula data

arXiv

引用

arXiv 2023年

作者： Abe, H. Abe, K. Abe, S. Acciari, V.A. Aguasca-Cabot, A. Agudo, I. Crespo, N. Alvarez Aniello, T. Ansoldi, S. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baack, D. Babić, A. Baktash, A. Bamba, A. Larriva, A. Baquero Baroncelli, L. de Almeida, U. Barres Barrio, J.A. Batković, I. Baxter, J. González, J. Becerra Bednarek, W. Bernardini, E. Bernardos, M.I. Medrano, J. Bernete Berti, A. Besenrieder, J. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Biland, A. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Bošnjak, Ž. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Busetto, G. Ordaz, A. Campoy Cardillo, M. Caroff, S. Carosi, A. Carosi, R. Carrasco, M.S. Carretero-Castrillo, M. Cassol, F. Castro-Tirado, A.J. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cornelia, A. Cortina, J. Costantini, H. Covino, S. D’Amico, G. D’Elia, V. Da Vela, P. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. DelPopolo, A. Deleglise, G. Delfino, M. Mendez, C. Delgado Mengual, J. Delgado Volpe, D. della Dellaiera, M. Depaoli, D. De Angelis, A. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Dominik, R.M. Prester, D. Dominis Donini, A. Dorner, D. Doro, M. Díaz, C. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Ramazani, V. Fallah Fariña, L. Fattorini, A. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Font, L. Coromina, L. Freixas Fröse, S. Fukami, S. Fukazawa, Y. López, R.J. Garcia Garcia, E. Garczarczyk, M. López, R.J. García Gasbarra, C. Gasparrini, D. Gasparyan, S. Gaug, M. Geyer, D. Paiva, J.G. Giesbrecht Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Grau, R. Green, D. Green, J.G. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Llorente, J. Herrera Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Institute for Cosmic Ray Research University of Tokyo 5-1-5 Kashiwa-no-ha Chiba Kashiwa277-8582 Japan Department of Physics Tokai University 4-1-1 Kita-Kaname Kanagawa Hiratsuka259-1292 Japan Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Tenerife La Laguna Spain Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Martí i Franquès 1 Barcelona08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Grupo de Electronica Universidad Complutense de Madrid Av. Complutense s/n Madrid28040 Spain RomeI-00136 Italy INFN Sezione di Trieste Università degli studi di Udine via delle scienze 206 Udine33100 Italy Rome Italy INAF - Osservatorio Astronomico di Roma Via di Frascati 33 Monteporzio Catone00040 Italy INFN Sezione di Napoli Via Cintia ed. G Napoli80126 Italy Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany Università di Padova INFN PadovaI-35131 Italy The Barcelona Institute of Science and Technology Campus UAB Bellaterra08193 Spain Univ. Savoie Mont Blanc CNRS Laboratoire d’Annecy de Physique des Particules - IN2P3 Annecy74000 France Department of Physics TU Dortmund University Otto-Hahn-Str. 4 Dortmund44227 Germany Zagreb10000 Croatia Universität Hamburg Institut für Experimentalphysik Luruper Chaussee 149 Hamburg22761 Germany Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan IPARCOS-UCM Instituto de Física de Partículas y del Cosmos EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain Faculty of Science and Technology Universidad del Azuay Cuenca Ecuador INAF - Osservatorio di Astrofisica e Scienza dello spazio di Bologna Via Piero Gobetti 93/3 Bologna40129 Italy Centro Brasileiro de Pesquisas Físicas Rua Xavier Sigaud 150 RJ Rio de Janeiro22290-180 Brazil INFN Sezione di Padova

Aims. LST-1, the prototype of the Large-Sized Telescope for the upcoming Cherenkov Telescope Array Observatory, is concluding its commissioning in Observatorio del Roque de los Muchachos on the island of La Palma. The proximity of LST-1 (Large-Sized Telescope 1) to the two MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes permits observations of the same gamma-ray events with both systems. Methods. We describe the joint LST-1+MAGIC analysis pipeline and use simultaneous Crab Nebula observations and Monte Carlo simulations to assess the performance of the three-telescope system. The addition of the LST-1 telescope allows the recovery of events in which one of the MAGIC images is too dim to survive analysis quality cuts. Results. Thanks to the resulting increase in the collection area and stronger background rejection, we find a significant improvement in sensitivity, allowing the detection of 30% weaker fluxes in the energy range between 200 GeV and 3 TeV. The spectrum of the Crab Nebula, reconstructed in the energy range ∼60 GeV to ∼10 TeV, is in agreement with previous measurements. Copyright © 2023, The Authors. All rights reserved.

关键词： Telescopes

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All-Electrical Determination of Crystal Orientation in Anisotropic Two-Dimensional Materials

引用

Physical Review Letters 2018年第8期120卷 086801-086801页

作者： Lintao Peng Spencer A. Wells Christopher R. Ryder Mark C. Hersam Matthew Grayson Applied Physics Graduate Program Northwestern University Evanston Illinois 60208 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Department of Electrical Engineering and Computer Science Northwestern University Evanston Illinois 60208 USA Department of Chemistry Northwestern University Evanston Illinois 60208 USA

The crystal orientation of an exfoliated black phosphorous flake is determined by purely electrical means. A sequence of three resistance measurements on an arbitrarily shaped flake with five contacts determines the three independent components of the anisotropic in-plane resistivity tensor, thereby revealing the crystal axes. The resistivity anisotropy ratio decreases linearly with increasing temperature T and carrier density reaching a maximum ratio of 3.0 at low temperatures and densities, while mobility indicates impurity scattering at low T and acoustic phonon scattering at high T.

关键词： Crystal orientation Electrical conductivity Semiconductors Transport phenomena Multilayer thin films Phosphorene Transition metal dichalcogenides Resistivity measurements

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Multi-wavelength study of the galactic PeVatron candidate LHAASO J2108+5157

arXiv

引用

arXiv 2022年

作者： Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. 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. Bordas, P. Buisson, C. Bulgarelli, A. Burelli, I. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Cassol, F. Cauz, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. D'Amico, G. Dalchenko, M. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. de Menezes, R. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Fiasson, A. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Giro, E. Gliwny, P. Godinovic, N. Grau, R. Green, D. Green, J. Gunji, S. 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. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Iwamura, Y. Jacquemont, M. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Le Flour, T. Linhoff, M. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Luque-Escamilla, P.L. Majumdar, P. Makariev, M. Mandat, D. Manganaro, M. Manicò, G. Mannheim, K. Mariotti, M. Marquez, P. Marsella, G. Martí, J. Martinez, O. Institute for Cosmic Ray Research University of Tokyo 5-1-5 Kashiwa-no-ha Kashiwa Chiba277-8582 Japan Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Martí i Franquès 1 Barcelona08028 Spain Instituto de Astrofísica de Andalucía CSIC Glorieta de la Astronomía s/n Granada18008 Spain Grupo de Electronica Universidad Complutense de Madrid Av. Complutense s/n Madrid28040 Spain INAF - Osservatorio Astronomico di Roma Via di Frascati 33 Monteporzio Catone00040 Italy INFN Sezione di Napoli Via Cintia ed. G Napoli80126 Italy Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany The Barcelona Institute of Science and Technology Campus UAB Bellaterra Barcelona08193 Spain Univ. Savoie Mont Blanc CNRS Laboratoire d'Annecy de Physique des Particules - IN2P3 Annecy74000 France Universität Hamburg Institut für Experimentalphysik Luruper Chaussee 149 Hamburg22761 Germany Graduate School of Science University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan EMFTEL department IPARCOS Universidad Complutense de Madrid Madrid28040 Spain INAF - Osservatorio di Astrofisica e Scienza dello spazio di Bologna Via Piero Gobetti 93/3 Bologna40129 Italy Centro Brasileiro de Pesquisas Físicas Rua Xavier Sigaud 150 RJ Rio de Janeiro22290-180 Brazil INFN Sezione di Padova Università degli Studi di Padova Via Marzolo 8 Padova35131 Italy Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Tenerife La Laguna Spain CIEMAT Avda. Complutense 40 Madrid28040 Spain Department of Physics TU Dortmund University Otto-Hahn-Str. 4 Dortmund44227 Germany INFN Sezione di Bari Politecnico di Bari via Orabona 4 Bari70124 Italy INFN Sezione di Trieste Università degli studi di Udine via delle scienze 206 Udine33100 Italy INFN Sezione di Catania Via S. Sofia 64 Catania95123 Italy Via del Fosso del Cavaliere 100 Roma00133 Italy Aix Marseill

Context: Several new ultrahigh-energy (UHE) gamma-ray sources have recently been discovered by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. These represent a step forward in the search for the so-called Galactic PeVatrons, the enigmatic sources of the Galactic cosmic rays up to PeV energies. However, it has been shown that multi-TeV gamma-ray emission does not necessarily prove the existence of a hadronic accelerator in the source;indeed this emission could also be explained as inverse Compton scattering from electrons in a radiation-dominated environment. A clear distinction between the two major emission mechanisms would only be made possible by taking into account multi-wavelength data and detailed morphology of the source. Aims: We aim to understand the nature of the unidentified source LHAASO J2108+5157, which is one of the few known UHE sources with no very high-energy (VHE) counterpart. Methods: We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good-quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its high-energy (HE) counterpart 4FGL J2108.0+5155. We used naima and jetset software packages to examine the leptonic and hadronic scenario of the multi-wavelength emission of the source. Results: We found an excess (3.7σ) in the LST-1 data at energies E > 3 TeV. Further analysis of the whole LST-1 energy range, assuming a point-like source, resulted in a hint (2.2σ) of hard emission, which can be described with a single power law with a photon index of Γ = 1.6 ± 0.2 the range of 0.3 − 100 TeV. We did not find any significant extended emission that could be related to a supernova remnant (SNR) or pulsar wind nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. We revealed a new pote

关键词： Cosmology

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Analyses of protein cores reveal fundamental differences between solution and crystal structures

arXiv

引用

arXiv 2019年

作者： Mei, Zhe Treado, John D. Grigas, Alex T. Levine, Zachary A. Regan, Lynne O'Hern, Corey S. Integrated Graduate Program in Physical & Engineering Biology Yale University New HavenCT06520 United States Department of Chemistry Yale University New HavenCT06520 United States Department of Mechanical Engineering & Materials Science Yale University New HavenCT06520 United States Graduate Program in Computational Biology & Bioinformatics Yale University New HavenCT06520 United States Department of Pathology Yale University New HavenCT06520 United States Department of Molecular Biophysics and Biochemistry Yale University New HavenCT06520 United States Institute of Quantitative Biology Biochemistry and Biotechnology Center for Synthetic and Systems Biology School of Biological Sciences University of Edinburgh Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States

There have been several studies suggesting that protein structures solved by NMR spectroscopy and x-ray crystallography show significant differences. To understand the origin of these differences, we assembled a database of high-quality protein structures solved by both methods. We also find significant differences between NMR and crystal structures|in the root-mean-square deviations of the Cα atomic positions, identities of core amino acids, backbone and sidechain dihedral angles, and packing fraction of core residues. In contrast to prior studies, we identify the physical basis for these differences by modelling protein cores as jammed packings of amino-acid-shaped particles. We find that we can tune the jammed packing fraction by varying the degree of thermalization used to generate the packings. For an athermal protocol, we find that the average jammed packing fraction is identical to that observed in the cores of protein structures solved by x-ray crystallography. In contrast, highly thermalized packing-generation protocols yield jammed packing fractions that are even higher than those observed in NMR structures. These results indicate that thermalized systems can pack more densely than athermal systems, which suggests a physical basis for the structural differences between protein structures solved by NMR and x-ray crystallography. Copyright © 2019, The Authors. All rights reserved.

关键词： X ray crystallography

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Low-temperature electron-phonon interaction of quantum emitters in hexagonal boron nitride

arXiv

引用

arXiv 2019年

作者： Grosso, Gabriele Moon, Hyowon Ciccarino, Christopher J. Flick, Johannes Mendelson, Noah Toth, Milos Aharonovich, Igor Narang, Prineha Englund, Dirk R. Advanced Science Research Center City University of New York Photonics Initiative New YorkNY United States Physics Program Graduate Center City University of New York New YorkNY United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA United States School of Mathematical and Physical Sciences University of Technology Sydney UltimoNSW2007 Australia Center for Computational Quantum Physics Flatiron Institute New YorkNY United States

关键词： Electron-phonon interactions

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Copper-Rich Thermoelectric Sulfides: Size-Mismatch Effect and Chemical Disorder in the [TS4]Cu6 Complexes of Cu26T2Ge6S32 (T=Cr, Mo, W) Colusites

引用

Advanced Materials 2019年第43期58卷 15601-15609页

作者： Kumar, Ventrapati Pavan Guélou, Gabin Lemoine, Pierric Raveau, Bernard Supka, Andrew R. Orabi, Rabih Al Rahal Al Fornari, Marco Suekuni, Koichiro Guilmeau, Emmanuel CRISMAT CNRS Normandie Univ ENSICAEN UNICAEN Caen14000 France Univ Rennes CNRS ISCR – UMR 6226 Rennes35000 France Department of Physics and Science of Advanced Materials Program Central Michigan University Mt. PleasantMI48859 United States Department of Applied Science for Electronics and Materials Interdisciplinary Graduate School of Engineering Sciences Kyushu University Kasuga Fukuoka816-8580 Japan Solvay Design and Development of Functional Materials Department Axel’One 87 avenue des Frères Perret Saint Fons Cedex69192 France

Herein, we investigate the Mo andWsubstitution for Cr in synthetic colusite, Cu26Cr2Ge6S32. Primarily, we elucidate the origin of extremely low electrical resistivity which does not compromise the Seebeck coefficient and leads to outstanding power factors of 1.94 mWm−1K−2 at 700 K in Cu26Cr2Ge6S32. We demonstrate that the abnormally long iono-covalent T–S bonds competing with short metallic Cu–T interactions govern the electronic transport properties of the conductive „Cu26S32" framework. We address the key role of the cationic size-mismatch at the core of the mixed tetrahedral–octahedral complex over the transport properties. Two essential effects are identified: 1) only the tetrahedra that are directly bonded to the [TS4]Cu6 complex are significantly distorted upon substitution and 2) the major contribution to the disorder is localized at the central position of the mixed tetrahedral–octahedral complex, and is maximized for x=1, i.e. for the highest cationic sizevariance, σ2. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Copper compounds

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