Article
Materials Science, Multidisciplinary
Sebastian Meyer, Bin Xu, Matthieu J. Verstraete, Laurent Bellaiche, Bertrand Dupe
Summary: The electrical control of magnons provides new possibilities for information transportation and processing in logic devices. The Dzyaloshinskii-Moriya (DM) interaction plays a crucial role in magnetoelectrical multiferroics by allowing direct control. This study uses density functional theory to determine the origin and strength of the DM interaction in BiFeO3 and highlights the significance of spin current-induced asymmetric potential in multiferroics.
Article
Chemistry, Multidisciplinary
Ningjing Luo, Zhufeng Hou, Chensheng Lin, Guo-Liang Chai
Summary: The stable ordered phases of W2C are determined by the attractive interaction of carbon vacancies in the L3-type lattice, while the disordered phase is stabilized by its configuration entropy. The phase transformation between different structures of W2C is facilitated by the migration of carbon atoms through a sequential intralayer mechanism.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Masayuki Ochi, Kazuhiko Kuroki
Summary: We theoretically investigate defect formation energies in LaOXS2 (X = Sb, Bi) using first-principles calculation. Oxygen vacancy is found to be relatively stable, with higher formation energy in X = Sb than in X = Bi. An interesting feature of X = Sb is the increased stability of in-plane sulfur atom vacancy compared to X = Bi, due to the formation of an Sb2 dimer and electron occupation of impurity energy levels. Cation defects and anion-cation antisite defects have positive formation energies under the chemical equilibrium condition. Fluorine likely replaces oxygen, with negative defect formation energy for both X = Sb and Bi, but significantly higher for X = Sb. Our study clarifies the stability of several point defects and suggests enhanced in-plane structural instability in X = Sb, possibly causing structural changes due to in-plane point defects.
Article
Physics, Multidisciplinary
Tamotsu Hashimoto, Hiroki Moriwake
Summary: Calculations of liquid BaTiO3 structure using FPMD simulations showed good agreement with experimental data, including structure factors and partial radial distribution functions. Temperature dependence of oxygen coordination number around titanium atoms and oxygen-titanium bond length also matched experimental results, with an increase in both as temperature decreased.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2021)
Article
Physics, Multidisciplinary
Marios Zacharias, Helene Seiler, Fabio Caruso, Daniela Zahn, Feliciano Giustino, Pantelis C. Kelires, Ralph Ernstorfer
Summary: Inelastic scattering experiments are crucial for mapping fundamental excitations of solids, with a particular focus on the role of multiphonon processes for phonon excitations. A new first-principles methodology has been developed to calculate the all-phonon quantum mechanical structure factor of solids, demonstrating the significance of multiphonon processes in the scattering patterns of black phosphorus. This approach represents a significant step towards interpreting static and time-resolved electron, x-ray, and neutron inelastic scattering data.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Marios Zacharias, Helene Seiler, Fabio Caruso, Daniela Zahn, Feliciano Giustino, Pantelis C. Kelires, Ralph Ernstorfer
Summary: Time-resolved diffuse scattering experiments are becoming more popular due to their ability to reveal nonequilibrium dynamics of crystal lattice vibrations with full momentum resolution. Researchers have developed a rigorous approach for calculating the all-phonon inelastic scattering intensity of solids from first-principles, showing that multiphonon interactions can be captured efficiently by exploiting crystal symmetries. The results demonstrate the predictive power of the method in calculating scattering patterns of various materials and provide insights into the dominating role of multiphonon excitations in different crystal structures.
Article
Chemistry, Physical
Stephen E. Weitzner, Tuan Anh Pham, Christine A. Orme, S. Roger Qiu, Brandon C. Wood
Summary: Ion (de)hydration is a key step in interfacial processes, and predicting its kinetics remains challenging. Static proxies like hydration energy and valence are useful but cannot fully capture the dynamic softness of the hydration shell. Dynamic descriptors are essential for correctly describing ion transfer processes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Joakim Brorsson, Anders E. C. Palmqvist, Paul Erhart
Summary: The study demonstrates that pseudobinary Ba8AlxGayGe46-x-y clathrates undergo order-disorder transitions with varying temperatures, with Ga-containing systems exhibiting lower transition temperatures than Al-containing systems. Experimental Al and Ga site occupation factors show partial agreement with simulated results, while the challenges in synthesizing Ba8AlxGe46-x and Ba8AlxSi46-x samples near the stoichiometric 16:30 composition ratio are explained.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Seyed Sepehr Mohajerani, Francesco Ricci, Fredrik L. Nordstrom
Summary: The binary T-X phase diagram of salicylic acid and benzoic acid was experimentally determined, showing two crystalline solid solutions with solid-state miscibility limits of 10.9 mol% and 82.5 mol% benzoic acid in salicylic acid at 25 degrees Celsius. The eutectic composition of 60.0 mol% benzoic acid in salicylic acid at a eutectic temperature of 112.69 degrees Celsius was also determined. Non-linearity in the Tammann plot was observed due to the temperature dependence of the solvus and compositional non-uniformity in the material.
Article
Chemistry, Physical
Yusuke Ogura, Tatsuya Yokoi, Kotaro Fujii, Masatomo Yashima, Katsuyuki Matsunaga
Summary: This study investigates the conduction mechanism of oxide ions in Si-deficient lanthanum silicate apatites using first-principles calculations. The results reveal that Si-deficient LSO can accommodate a small amount of excess oxide ions, which can diffuse rapidly along the c-axis through a push-pull mechanism. This mechanism significantly alters the energy profiles for ionic conduction and enhances ion conductivity.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Applied
Michael R. Walden, Cristian V. Ciobanu, Geoff L. Brennecka
Summary: This study validates the use of metrics of localized electronic states in predicting the trends in ferroic and dielectric properties of BiFeO3 and BiCrO3 under epitaxial strain using density-functional theory. The results suggest that localized electronic metrics can accurately predict the multiferroic characteristics of these systems, providing specific strain ranges.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Shuxiang Zhou, Hao Ma, Enda Xiao, Krzysztof Gofryk, Chao Jiang, Michael E. Manley, David H. Hurley, Chris A. Marianetti
Summary: This study investigates UO2 using DFT+U method at zero temperature, exploring the unstable electronic states with the control of f orbital occupation matrix. It is found that spin-orbit coupling and Hubbard U play crucial roles in the oxygen cage distortion, while magnetic ordering has a minimal impact. The phonon dispersion curves measurements using inelastic neutron scattering show good agreement with theoretical calculations.
Article
Chemistry, Physical
Qiang Wan, Yang Chen, Shulan Zhou, Jian Lin, Sen Lin
Summary: This study demonstrates that anatase TiO2 with oxygen vacancies on the surface can effectively hydrogenate acetylene to ethylene. Experimental confirmation shows that the reactivity is higher when oxygen vacancies are present after reduction. These findings have important implications for the development of selective hydrogenation catalysts based on earth-abundant materials.
JOURNAL OF MATERIALS CHEMISTRY A
(2021)
Article
Chemistry, Physical
Jordan Burns, Kristin A. Persson
Summary: In this study, oxygen evolution energies were calculated for different facets of a rock-salt-structured cation-disordered Li-excess, Mn-rich Li-ion cathode Li2MnO2F at different lithiation states. The results showed that Li2MnO2F is more resistant to oxygen loss compared to nonfluorinated counterparts, particularly the {110} and {112} facets. For the {100} facet, higher proportions of Li in an O coordination shell lead to lower oxygen evolution energy (E-O(similar to)) and facilitate oxygen loss. Surface fluorine has a weaker effect on increasing E-O(similar to) at higher lithiation states. Weak bonding interactions between Li and O were found to be associated with lower E-O(similar to) and a higher propensity for surface oxygen loss.
CHEMISTRY OF MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Tobias Dannegger, Andras Deak, Levente Rozsa, E. Galindez-Ruales, Shubhankar Das, Eunchong Baek, Mathias Klaeui, Laszlo Szunyogh, Ulrich Nowak
Summary: In this study, ab initio calculations were performed to investigate the tensorial exchange interactions of hematite, and a semiclassical Heisenberg spin model was used to understand its magnetic properties. Atomistic spin dynamics simulations were carried out to calculate the equilibrium properties and phase transitions of hematite, particularly the Morin transition. The computed isotropic and Dzyaloshinskii-Moriya interactions were found to agree well with experimental measurements of the Neel temperature and weak ferromagnetic canting angle. Our simulations revealed the delicate balance between dipole-dipole interactions and on-site anisotropies in determining the magnetic phase of the material. Comparison with spin-Hall magnetoresistance measurements on a hematite single crystal showed deviations of the critical behavior at low temperatures, which were attributed to the quantum nature of the fluctuations driving the phase transitions.
Article
Chemistry, Physical
James C. Womack, Lucian Anton, Jacek Dziedzic, Phil J. Hasnip, Matt I. J. Probert, Chris-Kriton Skylaris
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2018)
Article
Chemistry, Physical
Dawn Geatches, Ian Rosbottom, Richard L. Marchese Robinson, Peter Byrne, Phil Hasnip, Matt I. J. Probert, Dominik Jochym, Andrew Maloney, Kevin J. Roberts
JOURNAL OF CHEMICAL PHYSICS
(2019)
Review
Physics, Condensed Matter
N. D. Woods, M. C. Payne, P. J. Hasnip
JOURNAL OF PHYSICS-CONDENSED MATTER
(2019)
Article
Crystallography
Edward J. Higgins, Phil J. Hasnip, Matt I. J. Probert
Article
Physics, Condensed Matter
G. A. Naydenov, P. J. Hasnip, V. K. Lazarov, M. I. J. Probert
JOURNAL OF PHYSICS-CONDENSED MATTER
(2020)
Article
Materials Science, Multidisciplinary
Kenji Nawa, Demie Kepaptsoglou, Arsham Ghasemi, Philip Hasnip, Guillermo Barcena-Gonzalez, Giuseppe Nicotra, Pedro L. Galindo, Quentin M. Ramasse, Kohji Nakamura, Susannah C. Speller, Balati Kuerbanjiang, Thorsten Hesjedal, Vlado K. Lazarov
Summary: The study demonstrates that the weak van der Waals adhesion between Bi2Te3 and Ge can be overcome by forming an additional Te layer at their interface. First-principles calculations show that the formation of the additional Te layer is energetically favorable due to the strong hybridization between Te and Ge.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Computer Science, Interdisciplinary Applications
Matthew Smith, Arjen Tamerus, Phil Hasnip
Summary: In this article, the work of porting the CASTEP first-principles materials modeling program to accelerators using open accelerator (OpenACC) is presented. The challenges and opportunities of graphical processing units (GPU) architectures are discussed, along with the approach taken in the CASTEP OpenACC port. Early performance results show significant speed-ups, especially for materials simulations using nonlocal functionals.
COMPUTING IN SCIENCE & ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Thomas W. Keal, Alin-Marin Elena, Alexey A. Sokol, Karen Stoneham, Matt I. J. Probert, Clotilde S. Cucinotta, David J. Willock, Andrew J. Logsdail, Andrea Zen, Phil J. Hasnip, Ian J. Bush, Matthew Watkins, Dario Alfe, Chris-Kriton Skylaris, Basile F. E. Curchod, Qiong Cai, Scott M. Woodley
Summary: The transition to exascale computing enables simulations of unprecedented accuracy and complexity. The focus is on materials and molecular modeling that aim for high fidelity in silico experiments on technologically interesting complex systems. This progress presents significant challenges to software, particularly in exploiting parallelism and effectively managing workflows and data on such platforms.
COMPUTING IN SCIENCE & ENGINEERING
(2022)
Article
Chemistry, Physical
E. Karaca, P. J. P. Byrne, P. J. Hasnip, H. M. Tutuncu, M. I. J. Probert
Summary: The superconducting transition temperatures Tc of hexagonal Nb(2)AC (A: Al, S, Ge, As and Sn) were investigated using density functional perturbation theory to model the electron-phonon interaction. The results suggest that Nb2AlC may have the highest Tc among the materials studied, with superconductivity potentially being driven by the interactions of Nb 4d-state electrons with low-frequency phonons.
ELECTRONIC STRUCTURE
(2021)
Article
Materials Science, Multidisciplinary
Julio Cesar A. Do Nascimento, Adam Kerrigan, Philip J. Hasnip, Vlado K. Lazarov
Summary: In this study, we investigated the effect of stoichiometric pairs of antisite defects on the electronic structure and Seebeck coefficient of the Fe(2)VAlHeusler alloy. Our results demonstrate that the introduction of these defects can change the Fe2VAl from a semi-metal to a semiconductor, leading to an increase in the Seebeck coefficient within a certain range of doping concentrations and temperatures.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
E. Karaca, P. J. P. Byrne, P. J. Hasnip, M. I. J. Probert
Summary: A high-throughput computational method was used to predict 39 new superconductors in the Ti-based M(2)AX phases, and the best candidates were further studied using density functional theory. It was found that Ti2AlX (X: B, C and N) materials may have higher superconducting transition temperatures.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
G. A. Naydenov, P. J. Hasnip, V. K. Lazarov, M. I. J. Probert
JOURNAL OF PHYSICS-MATERIALS
(2019)
Article
Materials Science, Multidisciplinary
Evgeny Plekhanov, Phil Hasnip, Vincent Sacksteder, Matt Probert, Stewart J. Clark, Keith Refson, Cedric Weber
Article
Materials Science, Multidisciplinary
B. Kuerbanjiang, Y. Fujita, M. Yamada, S. Yamada, A. M. Sanchez, P. J. Hasnip, A. Ghasemi, D. Kepaptsoglou, G. Bell, K. Sawano, K. Hamaya, V. K. Lazarov