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Semiconductor science and technology 2022年第4期37卷 049501-049501页

作者： Alina Mreńca-Kolasińska Krzysztof Kolasiński Bartłomiej Szafran AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

Path-integral molecular dynamics with actively-trained and universal machine learning force fields

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arXiv 2025年

作者： Solovykh, A.A. Rybin, N.E. Novikov, I.S. Shapeev, A.V. Moscow119991 Russia Moscow119991 Russia Skolkovo Institute of Science and Technology Bolshoy boulevard 30 Moscow121205 Russia Digital Materials LLC Kutuzovskaya St. 4a Odintsovo143001 Russia HSE University Faculty of Computer Science Pokrovsky boulevard 11 Moscow109028 Russia Moscow Institute of Physics and Technology Institutsky lane 9 Moscow region Dolgoprudny141700 Russia Emanuel Institute of Biochemical Physics the Russian Academy of Sciences 4 Kosygin Street Moscow119334 Russia

Accounting for nuclear quantum effects (NQEs) can significantly alter material properties at finite temperatures. Atomic modeling using the path-integral molecular dynamics (PIMD) method can fully account for such effects, but requires computationally efficient and accurate models of interatomic interactions. Empirical potentials are fast but may lack sufficient accuracy, whereas quantum-mechanical calculations are highly accurate but computationally expensive. Machine-learned interatomic potentials offer a solution to this challenge, providing near-quantum-mechanical accuracy while maintaining high computational efficiency compared to density functional theory (DFT) calculations. In this context, an interface was developed to integrate moment tensor potentials (MTPs) from the MLIP-2 software package into PIMD calculations using the i-PI software package. This interface was then applied to active learning of potentials and to investigate the influence of NQEs on material properties, namely the temperature dependence of lattice parameters and thermal expansion coefficients, as well as radial distribution functions, for lithium hydride (LiH) and silicon (Si) systems. The results were compared with experimental data, quasi-harmonic approximation calculations, and predictions from the universal machine learning force field MatterSim. These comparisons demonstrated the high accuracy and effectiveness of the MTP-PIMD approach. Copyright © 2025, The Authors. All rights reserved.

关键词： Density functional theory

Magnetization reversal in Fe(001) films grown by magnetic field assisted molecular beam epitaxy

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arXiv 2023年

作者： Blyzniuk, B. Dziwoki, A. Freindl, K. Koziol-Rachwal, A. Madej, E. Mlyńczak, E. Szpytma, M. Wilgocka-Ślezak, D. Korecki, J. Spiridis, N. Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences Niezapominajek 8 Krakow30-239 Poland PREVAC sp. z o.o. Raciborska Str. 61 Rogów44-362 Poland AGH University of Krakow Faculty of Physics and Applied Computer Science al. Mickiewicza 30 Kraków30-059 Poland

We studied the influence of a magnetic field (MF) on epitaxial growth and magnetic properties of Fe(001) films deposited on MgO(001). Thanks to modular sample holders and a specialized manipulator in our multi-chamber ultrahigh vacuum system, the films could be deposited and annealed in an in-plane MF of 100 mT. In situ scanning tunnelling microscopy showed that MF had a strong influence on the film morphology, and, in particular, on the structure of surface steps. The magnetic properties were studied ex situ using magneto-optic Kerr effect (MOKE) magnetometry and microscopy. We showed that the moderate in-plane magnetic field applied during growth has the visible impact on the magnetic properties. The observed angular dependence of the MOKE loops and domain structures were discussed based on a magnetization reversal model. In particular we found that magnetization reversal occurs via 90° domains and the reversal differs for the no-field and in-field grown samples, in correlation with the film morphology. © 2023, CC BY.

关键词： Magnetization reversal

Scalable and Cost-Effective All-Chemical Production of Stable Gold-Coated Silver Thin-Films for High-Performance Plasmonic Optical Fiber Sensors 28

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Scalable and Cost-Effective All-Chemical Production of Stabl...

28th International Conference on Optical Fiber Sensors, OFS 2023

作者： dos Santos, Paulo S.S. Mendes, João P. Pastoriza-Santos, I. de Almeida, José M.M.M. Coelho, Luís C.C. INESC TEC - Institute of Systems and Computer Engineering Technology and Science Department of Physics Faculty of Sciences University of Porto Rua do Campo Alegre Porto4169-007 Portugal FEUP - Faculty of Engeneering of Unversity of Porto R. Dr. Roberto Frias Porto4200-465 Portugal CINBIO - Center of Research in Nanomaterials and Biomedicine Campus Universitario Lagoas Universidad de Vigo Marcosende Pontevedra Vigo36310 Spain SERGAS-UVIGO - Galicia Health Service Pontevedra Vigo36312 Spain UTAD Department of Physics University of Trás-os-Montes e Alto Douro Vila Real5001-801 Portugal

Long-term stability and high scalability are significant issues in plasmonic optical fiber sensors. This work presents a highly scalable and low-cost all-chemical approach for production of gold-coated silver thin-fil... 详细信息

ISBN: (纸本)9781957171302

关键词： Cost effectiveness

Performance Investigation of Instantaneous Reactive Power Control for 5 Level-Neutral Point Clamped Grid-Connected Photovoltaic Inverter

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Performance Investigation of Instantaneous Reactive Power Co...

Electrical Engineering and Automatic Control (ICEEAC), International Conference on

作者： Oumaymah Elamri Alla Eddine Toubal Maamar Charaf Chermite Moulay Rachid Douiri Mostefa Kermadi Saad Mekhilef LAMIGEP multidisciplinary research laboratory École Marocaine des Sciences de l'Ingénieur (EMSI) of Marrakech Marrakech Morocco Department of Electrical Systems Engineering Faculty of Technology University of M'hamed Bougara of Boumerdes Boumerdes Algeria Physics Department Control and Computer Science for Intelligent Systems and Green Energy Faculty of Science and Technology Cadi Ayyad University Marrakech Morocco School of Engineering University of Leicester Leicester United Kingdom Power Electronics and Renewable Energy Research Laboratory (PEARL) Kuala Lumpur Malaysia Swinburne University of Technology Hawthorn Vic Australia

ISBN: (数字)9798350349740

ISBN: (纸本)9798350349757

The utilization of solar energy in grid-connected photovoltaic installations has become increasingly significant. This article introduces a photovoltaic system seamlessly integrated with a three-phase network. The system employing a five-level Neutral Point Clamped (NPC) voltage source inverter is designed for a single-step connection to enhance power quality in the distribution network. The control technique employed for the efficient functioning of the photovoltaic system is based on the notion of instantaneous reactive power. Notably, this strategy is straightforward, operates the system throughout the day, and eliminates the need for Phase-Locked Loop (PLL) usage. The Pulse-Width Modulated (PWM) Current Controller sends switching signals to the NPC multilevel inverter, which does a great job of dynamic performance under steady-state and transient situations. The proportional-integral controller regulates the voltage of the Uninterruptible Power Supply DC bus capacitors. The proposed system undergoes comprehensive simulation validation under various irradiation levels.

关键词： Photovoltaic systems Reactive power Voltage source inverters Switches Solar energy Steady-state Transient analysis

Toward a generative modeling analysis of CLAS exclusive 2π photoproduction

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arXiv 2023年

作者： Alghamdi, T. Alanazi, Y. Battaglieri, M. Bibrzycki, L. Golda, A.V. Blin, A.N. Hiller Isupov, E.L. Li, Y. Marsicano, L. Melnitchouk, W. Mokeev, V.I. Montaña, G. Pilloni, A. Sato, N. Szczepaniak, A.P. Vittorini, T. Department of Computer Science Old Dominion University NorfolkVA23529 United States Department of Computer Science College of Computer Science and Information Technology Al-Baha University Al-Baha Alaqiq65779 Saudi Arabia Thomas Jefferson National Accelerator Facility Newport NewsVA23606 United States INFN sezione di Genova GenovaI-16146 Italy AGH University of Krakow Faculty of Physics and Applied Computer Science KrakówPL-30-059 Poland Faculty of Physics Lomonosov Moscow State University Moscow119991 Russia Institute for Theoretical Physics Tübingen University TübingenD-72076 Germany Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University Moscow119234 Russia CSSM and CDMPP Department of Physics University of Adelaide 5005 Australia Dipartimento di Scienze Matematiche e Informatiche Scienze Fisiche e Scienze della Terra Università degli Studi di Messina MessinaI-98166 Italy INFN Sezione di Catania CataniaI-95123 Italy Department of Physics Indiana University BloomingtonIN47405 United States Center for Exploration of Energy and Matter Indiana University BloomingtonIN47403 United States Università di Genova GenovaI-16146 Italy

AI-supported algorithms, particularly generative models, have been successfully used in a variety of different contexts. In this work, we demonstrate for the first time that generative adversarial networks (GANs) can be used in high-energy experimental physics to unfold detector effects from multi-particle final states, while preserving correlations between kinematic variables in multidimensional phase space. We perform a full closure test on two-pion photoproduction pseudodata generated with a realistic model in the kinematics of the Jefferson Lab CLAS g11 experiment. The overlap of different reaction mechanisms leading to the same final state associated with the CLAS detector’s nontrivial effects represents an ideal test case for AI-supported analysis. Uncertainty quantification performed via bootstrap provides an estimate of the systematic uncertainty associated with the procedure. The test demonstrates that GANs can reproduce highly correlated multidifferential cross sections even in the presence of detector-induced distortions in the training datasets, and provides a solid basis for applying the framework to real experimental data. Copyright © 2023, The Authors. All rights reserved.

关键词： Generative adversarial networks

Moment Tensor Potential and Equivariant Tensor Network Potential with explicit dispersion interactions

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arXiv 2025年

作者： Chalykh, Olga Korogod, Dmitry Novikov, Ivan S. Hodapp, Max Rybin, Nikita Shapeev, Alexander V. Skolkovo Institute of Science and Technology Skolkovo Innovation Center Bolshoy boulevard 30 Moscow143026 Russia Moscow Institute of Physics and Technology Institutsky lane 9 Moscow region Dolgoprudny141700 Russia HSE University Faculty of Computer Science Pokrovsky boulevard 11 Moscow109028 Russia Emanuel Institute of Biochemical Physics Russian Academy of Sciences 4 Kosygin Street Moscow119334 Russia Austria Digital Materials LLC Odintsovo Kutuzovskaya str. 4A Moscow Region143001 Russia

In this study, we investigate the effect of incorporating explicit dispersion interactions in the functional form of machine learning interatomic potentials (MLIPs), particularly in the Moment Tensor Potential and Equivariant Tensor Network potential for accurate modeling of liquid carbon tetrachloride, methane, and toluene. We show that explicit incorporation of dispersion interactions via D2 and D3 corrections significantly improves the accuracy of MLIPs when the cutoff radius is set to a commonly used value of 5—6 Å. We also show that for carbon tetrachloride and methane, a substantial improvement in accuracy can be achieved by extending the cutoff radius to 7.5 Å. However, for accurate modeling of toluene, explicit incorporation of dispersion remains important. Furthermore, we find that MLIPs incorporating dispersion interactions via D2 reach a close level of accuracy to those incorporating D3, and D2 is suitable for accurate modeling of the systems in the study, while being less computationally expensive. We evaluated the accuracy of MLIPs in dimer binding curves compared to ab initio data and in predicting density and radial distribution functions compared to experiments. Copyright © 2025, The Authors. All rights reserved.

关键词： Residence time distribution

Multi-photon time-of-flight MLEM application for the positronium imaging in J-PET

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arXiv 2023年

作者： Shopa, Roman Y. Dulski, Kamil Department of Complex Systems National Centre for Nuclear Research Świerk Otwock Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Center for Theranostics Jagiellonian University Kraków Poland INFN Laboratori Nazionali di Frascati Frascati Italy

We develop a positronium imaging method for the Jagiellonian PET (J-PET) scanners based on the time-of-flight maximum likelihood expectation maximisation (TOF MLEM). The system matrix elements are calculated on-the-fly for the coincidences comprising two annihilation and one de-excitation photons that originate from the ortho-positronium (o-Ps) decay. Using the Geant4 library, a Monte Carlo simulation was conducted for four cylindrical 22Na sources of β+ decay with diverse o-Ps mean lifetimes, placed symmetrically inside the two JPET prototypes. The estimated time differences between the annihilation and the positron emission were aggregated into histograms (one per voxel), updated by the weights of the activities reconstructed by TOF MLEM. The simulations were restricted to include only the o-Ps decays into back-to-back photons, allowing a linear fitting model to be employed for the estimation of the mean lifetime from each histogram built in the log scale. To suppress the noise, the exclusion of voxels with activity below 2% – 10% of the peak was studied. The estimated o-Ps mean lifetimes were consistent with the simulation and distributed quasi-uniformly at high MLEM iterations. The proposed positronium imaging technique can be further upgraded to include various correction factors, as well as be modified according to realistic o-Ps decay models. © 2023, CC BY.

关键词： Medical imaging

Efficient spin-orbit torque driven magnetization switching of GdFe using phosphorus-implanted platinum layers

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arXiv 2025年

作者： Shintaku, Kazuki Mathew, Arun Jacob Iwamoto, Akihisa Mohammadi, Mojtaba Awano, Hiroyuki Asada, Hironori Fukuma, Yasuhiro Department of Physics and Information Technology Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka820-8502 Japan Memory Engineering Laboratory Toyota Technological Institute Nagoya468-8511 Japan Graduate School of Sciences and Technology for Innovation Yamaguchi University Ube755-8611 Japan Research Center for Neuromorphic AI hardware Kyushu Institute of Technology Kitakyushu808-0196 Japan

The capability of the spin-orbit torque (SOT) generated via phenomena such as the spin Hall effect in heavy metals, in switching the magnetization of an adjacent magnetic material, has been studied extensively over the last decade. The efficiency of SOT generation is commonly quantified in terms of the spin Hall angle θSH. In this work, we demonstrate experimentally that implanting platinum (Pt) with phosphorus (P), resulting in Pt (P) d, where d denotes the implantation dose, increases θSH by a factor of 7, from 0.06 (d = 0) to 0.43 (d = 10 × 1016 ions/cm2). The enhanced θSH along with factors such as perpendicular magnetic anisotropy and resistivity, lead to reduction of the critical current density for switching the perpendicular magnetization of ferrimagnetic rare earth-transition metal alloy Gd26Fe74, by a factor of nearly 27, from 4.0 × 1011 A/m2 (d = 0) to 1.5 × 1010 A/m2 (d = 10 × 1016 ions/cm2). Further, the switching current density at zero thermal fluctuations and thermal stability factor were evaluated and found to be 2.0 × 1010 A/m2 and 61.4 (d = 10 × 1016 ions/cm2), with the latter being sufficiently above the required threshold for commercial memory applications. Our results suggest that Pt (P) could be a strong candidate in realizing efficient SOT driven magnetization switching leading to the development of improved memory and logic devices in the future. Copyright © 2025, The Authors. All rights reserved.

关键词： Iron alloys

Collisions of weakly-bound kinks in the Christ-Lee model

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arXiv 2023年

作者： Dorey, Patrick Gorina, Anastasia Romanczukiewicz, Tomasz Shnir, Yakov Department of Mathematical Sciences Durham University United Kingdom African Institute for Mathematical Sciences Muizenberg South Africa Osmanaga Mahallesi Vahapbey Sokak No:8 Kadiköy Istanbul34714 Turkey Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Institute of Physics University of Oldenburg OldenburgD-26111 Germany

We investigate soliton collisions a one-parameter family of scalar field theories in 1+1 dimensions which was first discussed by Christ and Lee [1]. The models have a sextic potential with three local minima, and for suitably small values of the parameter its kinks have an internal structure in the form of two weakly-bound subkinks. We show that for these values of the parameter kink collisions are best understood as an independent sequence of collisions of these subkinks, and that a static mode analysis is not enough to explain resonant structures emerging in this model. We also emphasise the role of radiation and oscillon formation in the collision process. © 2023, CC BY.

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