Article
Chemistry, Physical
Wenbo Sun, Guozheng Fan, Tammo van der Heide, Adam McSloy, Thomas Frauenheim, Balint Aradi
Summary: Density functional tight binding (DFTB) is a quantum chemical simulation method with low computational cost. A machine learning algorithm was introduced to optimize DFTB parameters, focusing on solids with defects. The trained model showed significant reduction in differences between DFTB and DFT, demonstrating the feasibility of the approach for simulating defective periodic systems.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Pilsun Yoo, Michael Sakano, Saaketh Desai, Md Mahbubul Islam, Peilin Liao, Alejandro Strachan
Summary: The research team developed a neural network reactive force field (NNRF) to describe the decomposition and reaction of the high-energy nitramine RDX. Trained and iteratively refined using data, NNRF demonstrated significantly higher accuracy compared to the current state of the art potentials.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
E. Shneyder, M. Zotova, S. Nikolaev, S. G. Ovchinnikov
Summary: This study investigates the influence of electron-phonon interaction on the insulator-metal transitions driven by doping in a strongly correlated system, using the polaronic version of the generalized tight-binding method. It analyzes a wide electron-phonon parameter range and demonstrates the relationship between transition features and system properties such as polaron and bipolaron crossovers, redistribution of spectral weight, orbital selectivity, flat-band formation, and pseudogap behavior of various origins.
Article
Materials Science, Multidisciplinary
Monodeep Chakraborty, Sankeerth S. Narayan, R. Vigneshwaran, Mona Berciu
Summary: Variational exact diagonalization is used to investigate the properties of single polarons in four different dual models, including short-range off-diagonal (Peierls) and longer-range diagonal (Holstein or breathingmode) couplings. The results show strong sensitivity to the range of the diagonal coupling and dependence on the specific form of the diagonal coupling, suggesting careful consideration is required when making quantitative comparisons with experimental data.
Article
Optics
Miroslav Kolesik
Summary: In this study, a simulator for semiconductor Bloch equations was used to investigate the tight-binding (TB) description of zinc blende structure as a model for high-harmonic generation. The results showed that the TB models of GaAs and ZnSe can accurately represent their second-order nonlinear coefficients and reproduce the measured high-harmonic spectra in reflection without adjustable parameters.
Article
Chemistry, Physical
Taiji Nakamura, Tomoko Yokaichiya, Dmitri G. Fedorov
Summary: In this study, a fast quantum-mechanical method was used to optimize atomic coordinates and cell parameters for a set of protein crystals, with good agreement between experimental and calculated structures. Sterical clashes in the experimental structures were corrected through simulations, and partition analysis was extended to treat periodic boundary conditions and analyze protein-solvent interactions in crystals.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Jian Lv, Yong Du, Yingbiao Peng, Cong Zhang, Jianzhan Long, Weibin Zhang
Summary: The C content has a significant effect on the microstructure and gradient structure of nitrogen-containing cermets. High C content leads to a decrease in the thickness of the gradient layer and a reduction in the number of hard particles and bright inclusions.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Physics, Condensed Matter
Tian-Xiang Liu, Li Mao, Mats-Erik Pistol, Craig Pryor
Summary: The proposed method of connecting atomistic and quasi-continuous models can speed up tight-binding calculations for large systems, reducing computation time while maintaining high accuracy. The numerical tests show significant improvements in efficiency with minimal loss of accuracy.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Physics, Condensed Matter
Javier E. Hasbun, Lok C. Lew Yan Voon, Morten Willatzen
Summary: An exact analytical model of charge dynamics for a chain of atoms with asymmetric hopping terms is proposed in this paper. The results, both analytical and numerical, demonstrate similar dynamics in the absence and presence of electron interactions. Additionally, the model is extended to the case of two atoms per cell and applied to the study of contact electrification between different atomic chains.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Jian Lv, Yong Du, Ming Lou, Kai Xu, Keke Chang
Summary: The traditional preparation method of cermet has its drawbacks in avoiding direct contact between different phases, leading to decreased strength and toughness. The introduction of (Ti,W)(C,N) solid-solution powder shows improved mechanical properties and wear resistance in the resulting cermet.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2022)
Article
Engineering, Multidisciplinary
Alexander V. Mamonov, Maxim A. Olshanskii
Summary: This paper presents a reduced order model (ROM) for numerical integration of a dynamical system with multiple parameters. The ROM utilizes compressed tensor formats to find a low rank representation for high-fidelity snapshots of the system state. The computational cost of the online phase depends only on tensor compression ranks, making it efficient and accurate.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Madison K. Brod, Shashwat Anand, G. Jeffrey Snyder
Summary: In recent years, the excellent performance of n-type Mg3Sb2 as a thermoelectric material has gained much attention. The high performance is attributed to the high valley degeneracy (NV) of the electron transport edge, resulting from the conduction band minimum (CBM) located at a low symmetry point in the first Brillouin zone. Bi alloying on the Sb site has been shown to improve electron mobility and performance. Previous studies have overlooked the importance of Sb orbitals in the low-symmetry CBM. This work demonstrates that the low-symmetry CBM is due to the interactions between Mg-s and Sb-p orbitals.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Physical
Mikhail Tsitsvero, Jenny Pirillo, Yuh Hijikata, Tamiki Komatsuzaki
Summary: Nuclear magnetic resonance (NMR) spectroscopy is a crucial technique in chemistry for obtaining accurate information about molecules. This study presents a machine learning (ML) method based on Gaussian process/deep kernel learning to predict, average, and analyze instantaneous chemical shifts of molecular conformations. The method was successfully applied to a trefoil knot molecule composed of 24 para-connected benzene rings.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Qile Li, Jackson S. Smith, Yuefeng Yin, Chutian Wang, Mykhailo Klymenko, Jared H. Cole, Nikhil Medhekar
Summary: Bismuth, with its unique properties, has been used as a prototype material to study topological electronic structures. By developing tight-binding models based on first-principles calculations, it has been shown that these models can accurately reproduce the electronic and topological features of two-dimensional bismuth allotropes. The models provide insight into the physical origin of novel band topology and perturbation effects in bismuth allotropes, serving as a starting point for exploring electron/spin transport and electromagnetic response in low-dimensional topological devices.
NEW JOURNAL OF PHYSICS
(2021)
Review
Materials Science, Ceramics
Lu Yang, Ji Xiong, Xiuxian Chen, Xiangrong Li, Chenjun Deng, Daojun Zhang, Liu Yi
Summary: This study assessed the growth of CVD composite coatings on three kinds of cermets and their high-temperature frictional properties. The nitrogen content was found to affect the crystallinity of the composite coating. The CVD coating with a C/N ratio of 7:3 showed the best comprehensive properties and lowest wear rate in high-temperature friction wear.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Anton Bochkarev, Yury Lysogorskiy, Sarath Menon, Minaam Qamar, Matous Mrovec, Ralf Drautz
Summary: The article presents an efficient framework for parametrization of atomic cluster expansion (ACE) models for elements, alloys, and molecules, and discusses some key issues in the parameterization process.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Computer Science, Interdisciplinary Applications
Genevieve Dusson, Markus Bachmayr, Gabor Csanyi, Ralf Drautz, Simon Etter, Cas van der Oord, Christoph Ortner
Summary: This study proposes an atomic cluster expansion method that uses a precomputation algorithm to obtain a complete set of basis functions and a fast recursive algorithm for efficient evaluation. It also discusses the challenges of basis optimization and parameter estimation in order to comprehensively analyze convergence to a high-fidelity reference model.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Sergei Starikov, Daria Smirnova, Tapaswani Pradhan, Ilia Gordeev, Ralf Drautz, Matous Mrovec
Summary: The recently developed angular-dependent potential for pure iron has been extended to the Fe-Cr-H ternary system, allowing for simulations of Fe-Cr alloys with various hydrogen concentrations. The model's angular-dependent format and machine learning-based development procedure strike a favorable balance between computational cost and parametrization reliability. Validation tests on binary metallic alloys and hydrogen interactions demonstrate the potential's applicability, especially in large-scale simulations of hydrogen diffusion near crystal defects.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
J. Salamania, D. G. Sangiovanni, A. Kraych, K. M. Calamba Kwick, I. C. Schramm, L. J. S. Johnson, R. Boyd, B. Bakhit, T. W. Hsu, M. Mrovec, L. Rogstrom, F. Tasnadi, I. A. Abrikosov, M. Oden
Summary: Through high-resolution scanning transmission electron microscopy, different types of dislocations in titanium nitride films are identified, and their effects on chemical bonding are revealed. The findings have significant implications for the design and interpretation of nanoscale and macroscopic properties of TiN.
MATERIALS & DESIGN
(2022)
Article
Materials Science, Multidisciplinary
Aleksei Egorov, Aparna P. A. Subramanyam, Ziyi Yuan, Ralf Drautz, Thomas Hammerschmidt
Summary: For large-scale atomistic simulations of magnetic materials, an analytic bond-order potential (BOP) for iron-cobalt is proposed in this study. The BOP captures the electronic structure of magnetic and nonmagnetic Fe-Co phases accurately and provides accurate predictions for various properties. It is suitable for atomistic simulations with thousands and millions of atoms.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yury Lysogorskiy, Anton Bochkarev, Matous Mrovec, Ralf Drautz
Summary: The atomic cluster expansion (ACE) is a new class of data-driven interatomic potentials that have a complete basis set. Automation of the construction of the training dataset and indication of model uncertainty are important for the development of any interatomic potential. This study compares two approaches for uncertainty indication of ACE models and finds that the extrapolation grade based on the D-optimality criterion is more efficient and allows for active exploration of new structures.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Sergei Starikov, Vahid Jamebozorgi, Daria Smirnova, Ralf Drautz, Matous Mrovec
Summary: Screw and edge dislocations in body-centered cubic transition metals exhibit distinct diffusion characteristics, with the migration along screw dislocations being faster due to their different atomic structures.
Article
Materials Science, Multidisciplinary
Ning Wang, Thomas Hammerschmidt, Tilmann Hickel, Jutta Rogal, Ralf Drautz
Summary: The effect of spin fluctuations on the alpha-gamma and gamma-8 phase transitions in iron was investigated using a tight-binding model. It was found that spin fluctuations influence the phase transitions through different mechanisms, with the alpha-gamma transition being mainly affected by the magnetic/electronic free-energy difference and the gamma-8 transition being influenced indirectly through spin-lattice coupling. The calculated transition temperatures were in good agreement with experimental values.
Article
Chemistry, Physical
Saba Kharabadze, Maxwell Meyers, Charlsey R. Tomassetti, Elena R. Margine, Igor I. Mazin, Aleksey N. Kolmogorov
Summary: The prediction of high-Tc superconductivity in hole-doped LixBC material led to attempts in synthesizing new materials with honeycomb B-C layers. However, the thermodynamic stability of Li-B-C compounds has not been thoroughly explored. This study uses density functional theory to characterize different Li-B-C phases and estimates the conditions required for delithiation. The study also identifies more natural and favorable Li2B2C configurations that are still above the thermodynamic stability threshold.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
S. Starikov, A. Abbass, R. Drautz, M. Mrovec
Summary: This study investigates temperature-induced disordering transitions of grain boundaries in body-centered cubic metals using classical atomistic simulations. The study reveals that gradual heating leads to continuous disordering of the grain boundary structure, accompanied by two complexion transitions, analogous to transitions described by the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young theory.
Article
Physics, Multidisciplinary
Anton Bochkarev, Yury Lysogorskiy, Christoph Ortner, Gaebor Csaenyi, Ralf Drautz
Summary: Traditionally, interatomic potentials neglect intermediate-range multiatom interactions. In this study, we introduce the multilayer atomic cluster expansion method that naturally includes these interactions, leading to improved accuracy and efficiency.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Senja Ramakers, Anika Marusczyk, Maximilian Amsler, Thomas Eckl, Matous Mrovec, Thomas Hammerschmidt, Ralf Drautz
Summary: This paper investigates the thermodynamic stability of different SiC polytypes and identifies that the differences in surface energy are likely the driving force for nucleation, while the differences in bulk thermodynamic stability slightly favor certain polytypes.
Article
Materials Science, Multidisciplinary
Hari Paudyal, Elena R. Margine
Summary: A new member of the TMD family, 2M-WS2, has been discovered to exhibit superconductivity with a critical temperature of 8.8 K, the highest among superconducting TMDs. Doping with Nb and Ta has been found to significantly enhance the superconducting properties of 2M-WS2, leading to a 50% increase in T-c, while doping with Mo and Se results in a monotonous decrease in T-c.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)