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Formation of spin-orbital entangled two-dimensional electron gas in layer delta-doped bilayer iridate LaδSr3Ir2O7

Physical Review Materials 2023年第11期7卷 114409-114409页

作者： Amit Chauhan Arijit Mandal B. R. K. Nanda Condensed Matter Theory and Computational Lab Department of Physics IIT Madras Chennai 36 India Center for Atomistic Modelling and Materials Design IIT Madras Chennai 36 India Institute for Advanced Simulation Forschungszentrum Jülich Jülich 52425 Germany

5d transition-metal oxides host a variety of exotic phases due to the comparable strength of Coulomb repulsion and spin-orbit coupling. Herein, by pursuing density-functional studies on a delta-doped quasi-two-dimensional iridate Sr3Ir2O7, where a single SrO layer is replaced by LaO layer, we predict the formation of a spin-orbital entangled two-dimensional electron gas (2DEG) which is sharply confined on two IrO2 layers close to the LaO layer. In this bilayer crystal structure, an existing potential well is further augmented with the inclusion of positively charged LaO layer which results in confining the extra valence electron made available by the La3+ ion. The confined electron is bound along crystal a direction and is highly mobile in the bc plane. A tight-binding model Hamiltonian involving the Ir−t2g orbitals is formulated to provide further insight into the formation of 2DEG. From the band structure point of view, now the existing half-filled Jeff=1/2 states are further electron doped to destroy the antiferromagnetic Mott insulating state of IrO2 layers near to the delta-doped layer. This leads to partially occupied Ir upper-Hubbard subbands which host the spin-orbital entangled 2DEG. The IrO2 layers far away from the interface remain insulating and preserve the collinear G-type magnetic ordering of pristine Sr3Ir2O7. The conductivity tensors calculated using semiclassical Boltzmann theory at room temperature reveal that the 2DEG exhibits large electrical conductivity of the order of 1019Sm−1s−1.

关键词： Electrical conductivity Electronic structure Magnetism Spin-orbit coupling Antiferromagnets Magnetic insulators Mott insulators Two-dimensional electron gas Boltzmann theory Density functional theory Electron-correlation calculations

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粉末床熔融的多材料铺粉过程中粉末扩散的数值研究

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Acta Mechanica Sinica 2023年第1期39卷 23-29页

作者：王林李二垒周宗彦张百成余艾冰 ARC Hub for Computational Particle Technology Department of Chemical & Biological Engineering Monash University Clayton VIC 3800 Australia Delft University of Technology Stevinweg 1 2628 CN Delft The Netherlands Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and Technology Nanchang 330013 China Beijing Advanced Innovation Center Materials Genome Engineering Advanced Material & Technology Institute University of Science and Technology Beijing Beijing 100083 China

粉末床熔融增材制造技术已应用于功能梯度材料的制造.文献中报道了一种材料成分沿垂直于粉末铺粉方向变化的新设计.基于此设计,本工作采用离散单元数值模拟研究了两种密度差异较大的金属粉末在铺粉过程中颗粒的偏析情况.结果发现,在铺... 详细信息

粉末床熔融增材制造技术已应用于功能梯度材料的制造.文献中报道了一种材料成分沿垂直于粉末铺粉方向变化的新设计.基于此设计,本工作采用离散单元数值模拟研究了两种密度差异较大的金属粉末在铺粉过程中颗粒的偏析情况.结果发现,在铺粉过程中,较大密度粉末(重颗粒)一侧的铺粉量小于较小密度粉末(轻颗粒)的一侧的铺粉量.这种现象表明重颗粒从粉末密度大的一侧向粉末密度较小的一侧扩散.这种扩散受铺粉速度影响较大,铺粉速度越快,扩散越明显.但粉末层厚度对扩散影响不大.结果还表明,重颗粒与轻颗粒间的粒径差异影响扩散较大,减小重颗粒的粒径可能是控制颗粒偏析的一种方案.

关键词：材料成分颗粒偏析功能梯度材料离散单元金属粉末密度差异增材制造技术扩散影响

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Complete Suppression of Phase Segregation in Mixed-Halide Perovskite Nanocrystals under Periodic Heating

arXiv

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arXiv 2023年

作者： Feng, Shengnan Duan, Rentong Ju, Yu Li, Shuyi Zhang, Chunfeng Tao, Shuxia Xiao, Min Wang, Xiaoyong National Laboratory of Solid State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Materials Simulation and Modelling Center for Computational Energy Research Department of Applied Physics Eindhoven University of Technology Eindhoven5600 MB Netherlands Department of Physics University of Arkansas FayettevilleAR72701 United States

Under continuous light illumination, it is known that localized domains with segregated halide compositions form in semiconducting mixed-halide perovskites, thus severely limiting their optoelectronic applications due to the negative changes in bandgap energies and charge-carrier characteristics. Here we deposit mixed-halide perovskite CsPbBr1.2I1.8 nanocrystals onto an indium tin oxide substrate, whose temperature can be rapidly changed by ~10 0C in a few seconds by applying or removing an external voltage. Such a sudden temperature change induces a temporary transition of CsPbBr1.2I1.8 nanocrystals from the segregated phase to the mixed phase, the latter of which can be permanently maintained when the light illumination is coupled with periodic heating cycles. These findings mark the emergence of a practical solution to the detrimental phase-segregation problem, given that a small temperature modulation is readily available in various fundamental studies and practical devices using mixed-halide perovskites. Copyright © 2023, The Authors. All rights reserved.

关键词： Nanocrystals

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Multistep stochastic mechanism of polarization reversal in orthorhombic ferroelectrics

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Physical Review B 2021年第18期104卷 184106-184106页

作者： Y. A. Genenko M.-H. Zhang I. S. Vorotiahin R. Khachaturyan Y.-X. Liu J.-W. Li K. Wang J. Koruza Materials Modelling Department of Materials and Earth Sciences Technical University of Darmstadt Otto-Berndt-Straße 3 64287 Darmstadt Germany Nonmetallic Inorganic Materials Department of Materials and Earth Sciences Technical University of Darmstadt Alarich-Weiss-Straße 2 64287 Darmstadt Germany Interdisciplinary Center for Advanced Materials Simulation Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Germany State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China

A stochastic model of electric-field-driven polarization reversal in orthorhombic ferroelectrics is advanced, providing a description of their temporal electromechanical response. The theory accounts for all possible parallel and sequential switching events. Application of the model to the simultaneous measurements of polarization and strain kinetics in a lead-free orthorhombic (K,Na)NbO3-based ferroelectric ceramic over a wide timescale of seven orders of magnitude allowed identification of preferable polarization switching paths, fractions of individual switching processes, and their activation fields. Particularly, the analysis revealed substantial contributions of coherent non-180° switching events, which do not cause macroscopic strain and thus mimic 180° switching processes.

关键词： Ferroelectricity Strain Ceramics Ferroelectrics Polycrystalline materials Polarization Stochastic analysis

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Morphology and microstructure studies of the zincalume steel joints using metal inert gas (MIG) process

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AIP Conference Proceedings 2023年第1期2847卷

作者： Walisijiang Tayier Shamini Janasekaran Vijaya Prakash Vijayasree Vin Cent Tai Center for Advanced Materials and Intelligent Manufacturing Faculty of Engineering Built Environment & Information Technology SEGi University Petaling Jaya 47810 Selangor Malaysia Faculty of Environmental Studies Universiti Putra Malaysia 43400 Seri Kembangan Selangor Malaysia Centre for Modelling and Simulation Faculty of Engineering Built Environment & Information Technology SEGi University 47810 Petaling Jaya Selangor Malaysia

The lap joint of Zincalume G550 steel is welded by Metal Inert Gas (MIG) welding and ER70S-6 filler wire. 16.5 – 17.5 v of welding voltage and 3 – 4.5 m/min of wire-speed are set in parameters under the 70 A of constant welding current. The welded specimens were cold-mounted and cut with a cutting machine and the cross-section of the joints was ground with three different abrasive papers (220,1000,2000) and etching with Ferric Chloride (FeCl3). The microstructure of the joint surface is investigated. The fine (at FZ) and coarse grains (at HAZ) are identified clearly. In experimental testing, it can be seen that high welding voltage and low wire speed produced high heat energy, which can be led to the creation high volume of perlite structure in the weld zone and the grain size of the HAZ (heat affected zone) was much bigger than FZ (fusion zone) during the MIG process. The welding voltage is a direct relationship with forming microstructure that the phase transformation increases when the welding voltage increases. However, low wire speed can be expanded the size of the weld region where the fine grains are observed. In the FZ, the perlite structure (a-Ferrite and cementite) moved between the FZ and the HAZ, and the cementite grain much formed under the high-temperature end of the FZ.

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A 3D-printed microfluidic device for fabricating the soft, hollow, double-network magnetic microrobots

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Microchemical Journal 2025年 215卷

作者： Jialin Wu Jie Wang Shanshan Xu Ruiping Zou Aibing Yu Minsu Liu Sheng Yan Institute for Advanced Study Shenzhen University Shenzhen 518060 China ARC Research Hub for Smart Process Design and Control Department of Chemical and Biological Engineering Monash University Clayton Victoria 3800 Australia Centre for Simulation and Modelling of Particulate Systems Southeast University Suzhou 215000 China Research Center for Smart Process Engineering Great Bay University Dongguan 523000 China Monash Suzhou Research Institute (MSRI) Monash University Suzhou 215000 China

Endovascular intervention has transformed minimally invasive surgery but faces challenges in device stiffness, navigability, and safety. Existing magnetic soft robots, while promising, often risk incomplete retrieval or lack structural adaptability for controlled drug delivery. Here, we present a 3D-printed microfluidic strategy to fabricate a hollow magnetic soft robot (HMSR) with a double-network hydrogel structure (ionically crosslinked sodium alginate and photopolymerized PEG-diacrylate) and customized magnetic particle distribution. The HMSR exhibits ultralow stiffness (2–3 orders of magnitude lower than commercial guidewires), tunable mechanical properties via component concentration and UV exposure, and hollow architecture for drug loading. A magnetic navigation platform enables precise maneuvering through complex vascular models (achieving ± 135° bending angles) and multi-path selection, with full retrieval capability to mitigate embolism risks. Drug release kinetics demonstrate rapid initial release (30-min burst phase) followed by sustained release (60-min maintenance), ideal for thrombolytic or chemotherapeutic applications. This work advances magnetic soft robotics for safer endovascular therapies.

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Characterization of Electronic Properties, Exchange Splitting and Ferromagnetic Arrangement in New Ti-Doped BaO

Research Square

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Research Square 2020年

作者： Hachemaoui, Malika Meskine, Mohamed Mokaddem, Allel Doumi, Bendouma Mogulkoc, Yesim Tadjer, Abdelkader Faculty of Sciences Department of Physics University of Saida Dr. Moulay Tahar Saida20000 Algeria Instrumentation and Advanced Materials Laboratory University Center of Nour Bachir El-Bayadh El-Bayadh 32000 Algeria University Center of Nour Bachir El-Bayadh El-Bayadh 32000 Algeria Department of Engineering Physics Ankara University Tandogan Ankara 06100 Turkey Modelling and Simulation in Materials Science Laboratory Physics Department Djillali Liabes University of Sidi Bel-Abbes Sidi Bel-Abbes22000 Algeria

We have studied the electronic structures, ferromagnetic properties, half-metallicity and exchange splitting in BaO doped with titanium such as Ba1-xTixO at concentration x = 0.125. The structural parameters of BaO and Ba0.875Ti0.125O compounds are calculated with generalised gradient approximation of Wu and Cohen, while their electronic structures, accurate band gaps and magnetic properties are evaluated by the use of the Tran-Blaha-modified Becke-Johnson potential. The changes of lattice parameter and bulk modulus of Ba0.875Ti0.125O are discussed with respect to the BaO. We have found that the Ba0.875Ti0.125O has a wide half-metallic ferromagnetic gap of 2.701 eV and a half-metallic gap of 0.803 eV with integral Bohr magneton of 2 μB, where its ferromagnetic state is characterised by the main contribution of the direct exchange splitting. Therefore, the Ba0.875Ti0.125O is true half-metallic ferromagnet with spin polarisation of 100 % and appears to be promising material for spintronics applications. © 2020, CC BY.

关键词： Electronic structure

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Corrigendum: provincial-scale assessment of direct air capture to meet China’s climate neutrality goal under limited bioenergy supply (2024 Environ. Res. Lett. 19 114021)

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Environmental Research Letters 2025年第2期20卷 029502-029502页

作者： Hanwoong Kim Yang Qiu Haewon McJeon Andres Clarens Parisa Javadi Can Wang Rui Wang Jiachen Wang Hanying Jiang Andy Miller Ryna Cui Jenna Behrendt Yang Ou Sha Yu Jay Fuhrman Joint Global Change Research Institute University of Maryland and Pacific Northwest National Laboratory College Park MD 20740 United States of America Graduate School of Green Growth and Sustainability (GGGS) Korea Advanced Institute of Science and Technology 291 Daehak-ro Yuseong-gu Daejeon 34141 Republic of Korea University of Virginia Department of Civil and Environmental Engineering University of Virginia Charlottesville VA 22904 United States of America State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 People’s Republic of China Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modelling Institute for Global Change Studies Tsinghua University Beijing 100084 People’s Republic of China Center for Global Sustainability School of Public Policy University of Maryland College Park MD United States of America College of Environmental Sciences and Engineering Peking University Beijing People’s Republic of China Institute of Carbon Neutrality Peking University Beijing People’s Republic of China

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Parameterizing empirical interatomic potentials for predicting thermophysical properties via an irreducible derivative approach: the case of ThO2and UO2

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Journal of physics. Condensed matter : an Institute of Physics journal 2025年第25期37卷 2025 Jun 4页

作者： Shuxiang Zhou Chao Jiang Enda Xiao Sasaank Bandi Michael Cooper Miaomiao Jin David H Hurley Marat Khafizov Chris A Marianetti Idaho National Laboratory 2525 Fremont Ave Idaho Falls Idaho 83402-1509 UNITED STATES. Department of Chemistry Columbia University 630 W. 168th St. New York NY 10032 New York New York 10027-7041 UNITED STATES. Department of Applied Physics and Applied Mathematics Columbia University 630 W. 168th St. New York NY 10032 New York New York 10027-7041 UNITED STATES. Materials Science in Radiation and Dynamics Group Los Alamos National Laboratory Bikini Atoll Rd Los Alamos NM United States Los Alamos New Mexico 87545 UNITED STATES. Nuclear Engineering Penn State University Park 205 Hallowell Bldg University Park Pennsylvania 16802-1204 UNITED STATES. Center of Advanced Modelling and Simulation Idaho National Laboratory PO Box 1625 Idaho Falls ID 83415-3413 USA Idaho Falls Idaho 83415 UNITED STATES. Mechanical and Aerospace Engineering The Ohio State University 201 W 19th Ave Columbus Ohio 43210-1132 UNITED STATES. Department of Applied Physics and Applied Mathematics Columbia University 500 West 120th Street New York NY 10027 USA New York New York 10027 UNITED STATES.

The accuracy of classical physical property predictions using molecular dynamics simulations is determined by the quality of the interatomic potentials. Here we introduce a training approach for empirical interatomic potentials (EIPs) which is well suited for capturing phonons and phonon-related properties. Our approach is based on direct comparisons of the second- and third-order irreducible derivatives between an EIP and the Born-Oppenheimer potential within density functional theory (DFT) calculations. Irreducible derivatives fully exploit space group symmetry and allow for training without redundant information. We demonstrate the fidelity of our approach in the context of ThOand UO, where we optimize parameters of an embedded-atom method potential in addition to core-shell interactions. Our EIPs provide thermophysical properties in good agreement with DFT and outperform widely utilized EIPs for phonon dispersion and thermal conductivity predictions. Reasonable estimates of thermal expansion and formation energies of Frenkel pairs are also obtained.

关键词： density functional theory empirical potential nuclear fuel phonon phonon transport

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An environment for sustainable research software in Germany and beyond: Current state, open challenges, and call for action

arXiv

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arXiv 2020年

作者： Anzt, Hartwig Bach, Felix Druskat, Stephan Löffler, Frank Loewe, Axel Renard, Bernhard Y. Seemann, Gunnar Struck, Alexander Achhammer, Elke Aggarwal, Piush Appel, Franziska Bader, Michael Brusch, Lutz Busse, Christian Chourdakis, Gerasimos Dabrowski, Piotr W. Ebert, Peter Flemisch, Bernd Friedl, Sven Fritzsch, Bernadette Funk, Maximilian D. Gast, Volker Goth, Florian Grad, Jean-Noël Hermann, Sibylle Hohmann, Florian Janosch, Stephan Kutra, Dominik Linxweiler, Jan Muth, Thilo Peters-Kottig, Wolfgang Rack, Fabian Raters, Fabian H.C. Rave, Stephan Reina, Guido Reißig, Malte Ropinski, Timo Schaarschmidt, Joerg Seibold, Heidi Thiele, Jan P. Uekerman, Benjamin Unger, Stefan Weeber, Rudolf Germany Innovative Computing Lab University of Tennessee KnoxvilleTN United States Department of English Studies Friedrich Schiller University Jena Germany Germany Department of Computer Science Humboldt-Universität zu Berlin Germany Heinz Nixdorf Chair for Distributed Information Systems Friedrich Schiller University Jena Germany Michael Stifel Center Jena Germany Center for Computation and Technology Louisiana State University Baton Rouge United States Germany Robert Koch Institute Berlin Germany Hasso Plattner Institute Faculty of Digital Engineering University of Potsdam Germany Institute for Experimental Cardiovascular Medicine University Heart Centre Freiburg Bad Krozingen Germany Faculty of Medicine University of Freiburg Freiburg Germany Matters of Activity. Image Space Material. Cluster of Excellence at Humboldt-Universität zu Berlin Germany Technische Universität München Germany Language Technology Lab Universität Duisburg-Essen Germany Germany Department of Informatics Technical University of Munich Germany Technische Universität Dresden Germany Deutsches Krebsforschungszentrum Heidelberg Germany Scientific Computing in Computer Science Technical University Munich Germany School of Computing Communication and Business Hochschule für Technik und Wirtschaft Berlin Germany Center for Bioinformatics Saar Saarland Informatics Campus Germany Institute for Modelling Hydraulic and Environmental Systems University of Stuttgart Germany Berlin Institute of Health Germany Scientific Computing Alfred Wegener Institute Helmholtz Center for Polar and Marine Research Bremerhaven Germany Max-Planck-Gesellschaft e.V. Institut für Theoretische Physik und Astrophysik Universität Würzburg Germany Institut für Computerphysik University of Stuttgart Germany University Library University of Stuttgart Germany Universität Bremen Germany Max Planck Institute of Molecular Cell Biology and Genetics Dresden Germany European Molecular Biology Laboratory Heidelb

Research software has become a central asset in academic research. It optimizes existing and enables new research methods, implements and embeds research knowledge, and constitutes an essential research product in itself. Research software must be sustainable in order to understand, replicate, reproduce, and build upon existing research or conduct new research effectively. In other words, software must be available, discoverable, usable, and adaptable to new needs, both now and in the future. Research software therefore requires an environment that supports sustainability. Hence, a change is needed in the way research software development and maintenance are currently motivated, incentivized, funded, structurally and infrastructurally supported, and legally treated. Failing to do so will threaten the quality and validity of research. In this paper, we identify challenges for research software sustainability in Germany and beyond, in terms of motivation, selection, research software engineering personnel, funding, infrastructure, and legal aspects. Besides researchers, we specifically address political and academic decision-makers to increase awareness of the importance and needs of sustainable research software practices. In particular, we recommend strategies and measures to create an environment for sustainable research software, with the ultimate goal to ensure that software-driven research is valid, reproducible and sustainable, and that software is recognized as a first class citizen in research. This paper is the outcome of two workshops run in Germany in 2019, at deRSE19 - the first International Conference of Research Software Engineers in Germany - and a dedicated DFG-supported follow-up workshop in Berlin. Copyright © 2020, The Authors. All rights reserved.

关键词： Software design

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