Article
Chemistry, Applied
Manal Benyoussef, Halima Zaari, Jamal Belhadi, Youssef El Amraoui, Hamid Ez-Zahraouy, Abdelilah Lahmar, Mimoun El Marssi
Summary: The properties of Na-0.5(Bi3/4RE1/4)(0.5)TiO3 compounds were investigated using first-principles calculations and experimental measurements. It was found that compositions with high polarization values exhibit a higher TiO6 distortion, and the effect of rare-earth elements on polarization was confirmed experimentally. The investigation of electronic properties revealed the emergence of magnetization due to the 4f orbital effect of rare-earth elements. Additionally, the study of chemical ordering showed increased relaxor properties in rare-earth doped compositions.
JOURNAL OF RARE EARTHS
(2022)
Article
Materials Science, Multidisciplinary
Prashant Singh, Tyler Del Rose, Guillermo Vazquez, Raymundo Arroyave, Yaroslav Mudryk
Summary: In this study, a descriptor-based machine-learning approach was employed to assess the effect of chemical alloying on the formation enthalpy of rare-earth intermetallics. A rare-earth database was developed using high-throughput density-functional theory (DFT) with more than 600 compounds. The machine-learning method based on SISSO was used to train and test the formation enthalpies, and the complex lattice function was used to investigate the effect of transition metal alloying on energy stability. The study provides quantitative guidance for compositional considerations and facilitates the discovery of new metastable materials.
Article
Physics, Multidisciplinary
Abdulaziz H. Al-Aswad, Fahhad H. Alharbi
Summary: Developing a general kinetic energy density within orbital-free density functional theory is crucial. This study provides a guide by determining the largest spatial density derivative order for the kinetic energy density.
Article
Materials Science, Ceramics
Juanli Zhao, Wai-Yim Ching, Mengling Lai, Yun Fan, Jiancheng Li, Yiran Li, Wenxian Li, Bin Liu
Summary: In this study, the stabilities of (1 0 0), (1 1 0), and (1 1 1) surfaces of rare-earth zirconate pyrochlores were investigated. It was found that the (1 1 0) surface has the lowest surface formation energy and exhibits characteristics of oxygen vacancy segregation. These findings are important for understanding the surface structure and oxygen vacancy behavior, and can guide the optimization of surface properties for nanocrystalline rare-earth zirconates.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Prashant Singh, Tyler Del Rose, Yaroslav Mudryk
Summary: The thermodynamic stability of disordered rare-earth phases SmX2 and Sm10X21 (X = Ni, Pd) was investigated using machine-learning based analytical descriptor and first-principles density functional theory methods. The contrasting phase stability between Ni and Pd compounds in the cubic Laves phase was explored through thermodynamic convex hull analysis and electronic-structure analysis. The study highlights the importance of ab-initio methods and computationally inexpensive analytical descriptors in analyzing the thermodynamic and electronic properties of rare-earth compounds.
Article
Chemistry, Physical
Kevin Ryczko, Sebastian J. Wetzel, Roger G. Melko, Isaac Tamblyn
Summary: In this study, voxel deep neural networks were used to predict energy densities and functional derivatives in electron kinetic energies for the Thomas-Fermi model and Kohn-Sham density functional theory calculations. The researchers demonstrated that the ground-state electron density of a graphene lattice can be directly found via minimization without the need for a projection scheme, using a voxel deep neural network trained with the Thomas-Fermi model. Additionally, they were able to predict the kinetic energy of a graphene lattice with chemical accuracy after training from only two Kohn-Sham density functional theory calculations. The researchers also identified a sampling issue in Kohn-Sham density functional theory calculations and proposed future work to address this problem.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Biochemistry & Molecular Biology
Mikhail S. Kuklin, Kim Eklund, Jarno Linnera, Artturi Ropponen, Nikolas Tolvanen, Antti J. Karttunen
Summary: In this study, the structural properties, magnetic ground states, and fundamental electronic properties of 100 binary d-metal oxides were systematically investigated using hybrid density functional methods and localized basis sets. The PBE0 hybrid functional method was found to accurately describe the structural properties of most d-metal oxides, except for molecular oxides with weak intermolecular forces. A database of optimized geometries and magnetic ground states was provided for future studies on the more complex properties of binary d-metal oxides.
Article
Physics, Multidisciplinary
W. Thajitr, W. Busayaporn, D. P. Rai, W. Sukkabot
Summary: Using the DFT + U method, this study investigates the electronic and magnetic properties of transition metal mono- and co-doped MoX2 monolayers. The results show that the electronic structures and magnetic properties of these monolayers can be effectively controlled by the embedded transition metal atoms, and the magnetism is induced by the double exchange mechanism. V, Cr, and Co are identified as the energetically preferable substitutional dopants, and Mn, Fe, and Co doped-MoX2 and (Mo, Co, Co) Se-2 monolayers exhibit half-metallic behavior with perfect spin polarization.
Article
Polymer Science
Leonardo Anchique, Jackson J. Alcazar, Andrea Ramos-Hernandez, Maximiliano Mendez-Lopez, Jose R. Mora, Norma Rangel, Jose Luis Paz, Edgar Marquez
Summary: The study investigates the molecular interactions between antibiotics and NSAIDs with chitosan and graphene oxide as potential adsorbents, finding graphene oxide and chitosan as promising adsorbents for removing emerging pollutants from water.
Article
Chemistry, Multidisciplinary
Eva Prinz, Grisha Spektor, Michael Hartelt, Anna-Katharina Mahro, Martin Aeschlimann, Meir Orenstein
Summary: By tailoring the local and global geometries of vortex generators, arbitrary switching in the delivered plasmonic angular momentum can be achieved, providing a new method for plasmonic manipulation. The precise control over the generation and rotation direction of high-order plasmonic vortices was demonstrated, as well as the capability to create complex topological fields.
Article
Chemistry, Physical
Seetha Lakshmy, Gopal Sanyal, Antara Vaidyanathan, Saju Joseph, Nandakumar Kalarikkal, Brahmananda Chakraborty
Summary: The research investigates the sensing capabilities of Ti-decorated MoS2 for catechol through DFT simulation, revealing that Ti-decorated MoS2 has higher binding energy and may be a promising nanomaterial for catechol detection.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Aysenur Gencer, Sezgin Aydin, Ozge Surucu, Xiaotian Wang, Engin Deligoz, Gokhan Surucu
Summary: In this study, the hydrogen storage properties of Li-decorated Hf2CF2 MXene layer were investigated using first-principles calculations. The results show that the Li-decorated layer exhibits stable and convenient adsorption characteristics, making it a promising candidate for hydrogen storage applications.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Inorganic & Nuclear
S. Assa Aravindh, Iman S. Roqan, Hussain Alawadhi
Summary: The study showed that Eu doping in ZnO clusters is more favorable than Mg, helping in reducing the formation energy of point defects and inducing spin polarization. Eu-Eu doping prefers ferromagnetic orientation, and spin flip is induced by Eu in the Eu-Mg configuration.
JOURNAL OF CLUSTER SCIENCE
(2021)
Article
Chemistry, Physical
Chunlei Zhang, Xia Zhu, Chenliang Peng, Chaoyi Guo
Summary: The a-zirconium phosphate demonstrates a potential for recycling rare earth ions in tailwater due to the presence of abundant surface-POH groups and a layered structure. Experimental and DFT calculation methods were used to study the adsorption behaviors and mechanism of rare earth La3+ on the material. The results show that La3+ is mainly adsorbed through ion exchange with surface-POH protons, and the presence of impurity Al3+ has a significant influence on the adsorption of La3+.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Phil A. LeMaitre, Russell B. Thompson
Summary: In this article, a representation of polymer self-consistent field theory, equivalent to quantum density functional theory, is proposed using non-orthogonal basis sets. The molecular integrals and self-consistent equations for spherically symmetric systems using Gaussian basis functions are derived, and the binding energies and radial electron densities of neutral atoms hydrogen through krypton are calculated. A precise electron self-interaction correction is employed, and the Pauli-exclusion principle is enforced using the concept of polymer excluded-volume. The study examines the atoms hydrogen through neon without certain approximations, allowing for the observation of spontaneous shell structure.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2023)
Article
Physics, Applied
Amit Samanta, Joel B. Varley, Vincenzo Lordi
Summary: Using hybrid functional-based density functional theory calculations, the study analyzed the structure and kinetics of defects in hydrogen-doped In2O3 films synthesized through different routes. The results indicate that H+ is the dominant defect species and water molecules split into H+ and OH-. The defects do not cluster but remain spatially distributed throughout the films.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
E. F. O'Bannon, M. J. Lipp, J. S. Smith, Y. Meng, P. Soderlind, D. Young, Zs Jenei
Summary: In this study, the atomic volume and elastic constants of Ag were measured using a toroidal diamond anvil cell, with corrections for non-hydrostaticity made to the experimental results. It was found that the fcc structure of Ag remains stable up to 416GPa. Additionally, theoretical results indicate a shift in energy favoring the bcc structure over the fcc structure of Ag at certain pressures.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Multidisciplinary
E. F. O'Bannon, P. Soderlind, D. S. Sneed, M. J. Lipp, H. Cynn, J. S. Smith, C. Park, Z. S. Jenei
Summary: Through experimental and theoretical studies, the authors found no evidence of isostructural transitions in zirconium at high pressures, showing a smooth compression curve and consistent with previous findings.
HIGH PRESSURE RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Per Soderlind, Lin H. Yang, Alexander Landa, Amanda Wu
Summary: In this study, elasticity, lattice dynamics, and thermal expansion of uranium and U-6Nb alloy were calculated using DFT+OP density functional theory. It was found that introducing niobium into uranium softens the elastic moduli, particularly the shear modulus, making the material more ductile. The combination of a harmonic model with DFT+OP electronic structure successfully replicated the lattice dynamics and thermal expansion in alpha uranium.
APPLIED SCIENCES-BASEL
(2021)
Article
Chemistry, Physical
Chang-Eun Kim, Jiwoo Lee, Aron Walsh, Vincenzo Lordi, David F. Bahr
Summary: This study used density functional theory to calculate the energy and electronic structure of graphene models with different curvatures and hydrogen adsorption sites. The study found that the orientation of ripples affects the bandgap of graphene, while the adsorption energy of hydrogen depends on the curvature. Adsorbed hydrogen alters the curvature, resulting in weakened adsorption on neighboring sites, explaining the experimentally observed dynamic equilibrium stoichiometry of hydrogenated graphene.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Per Soderlind, Emily E. Moore, Christine J. Wu
Summary: In this study, the high-temperature thermodynamic properties of actinide monocarbides and mononitrides (ThC, ThN, UC, UN, PuC, and PuN) were calculated using first-principles electronic-structure theory. The electronic structure was modeled using density-functional theory (DFT) with full relativistic effects and spin-orbit interaction. Orbital-orbital interactions were taken into account using a parameter-free orbital-polarization (OP) technique, which was found to be essential for the 5f electrons in plutonium. The self-consistent ab initio lattice dynamics (SCAILD) method was used to capture strong anharmonicity and the temperature dependence of lattice vibrations. The calculated free energies and heat capacities were compared with results from quasi-harmonic (QH) theory and experiments, and CALPHAD assessments were used for uranium and plutonium compounds. Generally, the anharmonic relativistic approach showed good agreement with CALPHAD and experiments. However, for thorium compounds, the comparison with QH modeling of the free energy at lower temperatures was favorable but less favorable for the heat capacity.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Alexander Landa, Per Soderlind, Emily E. Moore, Aurelien Perron
Summary: Ni-doped Sm(Fe1-xCox)(12) alloys have been investigated for their magnetic properties. It has been found that replacing a certain amount of Fe and Co with Ni can increase the saturation magnetization of the alloys without affecting the anisotropy field or Curie temperature. This makes Ni a thermodynamic stabilizer with the spin moment aligned parallel to that of the SmFe12 compound.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Per Soederlind, Alexander Landa, Randolph Q. Hood, Emily E. Moore, Aurelien Perron, Joseph T. McKeown
Summary: We have presented a study on the high-temperature thermodynamic properties of graphite using first-principles anharmonic theory. Our results demonstrate that the inclusion of anharmonic lattice vibrations is crucial for accurate thermodynamic quantities above 1000 K.
APPLIED SCIENCES-BASEL
(2022)
Article
Nanoscience & Nanotechnology
Aedan Gardill, Ishita Kemeny, Yanfei Li, Maryam Zahedian, Matthew C. Cambria, Xiyu Xu, Vincenzo Lordi, Adam Gali, Jeronimo R. . Maze, Jennifer T. Choy, Shimon Kolkowitz
Summary: Super-resolution Airy disk microscopy, a novel technique presented in this study, allows nanoscale microscopy in a standard confocal microscope without specialized optics. The technique, combined with ground state depletion, successfully images and controls NV centers in diamond below the diffraction limit, achieving more than 14-fold improvement in resolution compared to the conventional limit.
Article
Physics, Applied
Amit Samanta, Stephan Friedrich, Kyle G. Leach, Vincenzo Lordi
Summary: Several current searches for physics beyond the standard model are focused on electron-capture decay of radionuclides implanted in cryogenic high-resolution sensors. Understanding the effects of the host material on the electron energy levels is necessary for accurate measurements. Using density-functional theory, the electronic structure of lithium in different atomic environments of a polycrystalline tantalum absorber film was modeled. The results show variation in binding energies and broadening of energy levels due to lattice sites, grain boundaries, and impurities, contributing to sensor peak broadening but not fully explaining it.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Multidisciplinary
M. C. Cambria, A. Norambuena, H. T. Dinani, G. Thiering, A. Gardill, I. Kemeny, Y. Li, V. Lordi, A. Gali, J. R. Maze, S. Kolkowitz
Summary: In this study, measurements of spin-lattice relaxation of the nitrogen-vacancy (NV) center were conducted as a function of temperature from 9 to 474 K. It was found that the temperature dependence of the relaxation rates can be explained by a theory of Raman scattering due to second-order spin-phonon interactions. The study also suggests that the high-temperature behavior of NV spin-lattice relaxation is dominated by interactions with two groups of quasi-localized phonons.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Per Soderlind, Alexander Landa, Emily E. Moore, Aurelien Perron, John Roehling, Joseph T. McKeown
Summary: In this study, high-temperature thermodynamic properties of gamma-phase uranium were investigated using first-principles, relativistic, and anharmonic theory. The proposed methodology, which includes density-functional theory (DFT) with spin-orbit coupling and self-consistent orbital-polarization (OP) mechanism, provides a more accurate treatment of magnetism and modeling of anharmonic lattice vibrations. The results were compared to CALPHAD modeling, other ab initio methods, and experimental data, showing that the all-electron DFT approach in combination with OP and SCAILD produces Gibbs free energy and heat capacity that are in good agreement with CALPHAD and experimental results, with significant thermal dependence due to the electronic contribution.
APPLIED SCIENCES-BASEL
(2023)
Article
Materials Science, Multidisciplinary
M. G. Gorman, C. J. Wu, R. F. Smith, L. X. Benedict, C. J. Prisbrey, W. Schill, S. A. Bonev, Z. C. Long, P. Soderlind, D. Braun, D. C. Swift, R. Briggs, T. J. Volz, E. F. O'Bannon, P. M. Celliers, D. E. Fratanduono, J. H. Eggert, S. J. Ali, J. M. McNaney
Summary: This article reports the experimental measurement of the compressibility of tantalum after compression, provides data on the cold compression curve of tantalum, and constructs an equation of state model with 2% uncertainty in pressure at 1 TPa. This model can be used as a pressure scale for laser-heated compression experiments to study the physical properties under extreme conditions such as planetary interiors.
Article
Materials Science, Multidisciplinary
D. T. Sneed, P. Soderlind, E. F. O'Bannon, H. Cynn, D. Smith, J. S. Smith, C. Park, Zs Jenei
Summary: In this study, we experimentally and theoretically compressed dysprosium metal using the soft pressure transmitting medium neon up to pressures of 182 GPa and 300 GPa, respectively. Our angle-dispersive x-ray powder diffraction data revealed anisotropic compression behavior in the high-pressure polymorphs, indicating changes in the electron density distribution across its polymorphic landscape. By comparing the monoclinic (mC4) and orthorhombic (oF16) structures as collapsed structures for dysprosium above 82 GPa, we confirmed that the oF16 structure provides a better fit to our data than the previously reported mC4 structure. Furthermore, we observed similar anisotropic compression behavior in the lattice parameters of the oF16 structure, with a turning point above 160 GPa, suggesting a potential phase transition at much higher pressures than achieved in this study. Density functional theory calculations indicate that the isosymmetric oF8 structure is the likely candidate for this new high-pressure phase, with lower energy than the oF16 structure above 275 GPa.
Article
Materials Science, Multidisciplinary
E. F. O'Bannon, O. S. Pardo, P. Soderlind, D. Sneed, M. J. Lipp, C. Park, Zs. Jenei
Summary: This study investigates the structural stability of praseodymium metal under high pressures using experiments and density functional theory. The results show that the ??-U structure of praseodymium is stable up to 185 GPa, and no evidence of the proposed transition to a primitive orthorhombic phase above 150 GPa was observed.