Article
Spectroscopy
Yi-Wei Fan, Huai-Qian Wang, Hui-Fang Li
Summary: The study on hydrated clusters Co(H2O)(n)(-) in gas phase using DFT coupled with stochastic kicking method reveals that the global minimum structure of Co(H2O)(n)(-) exhibits a low-symmetry pattern. The Co- ion tends to be located at the vertex site of the water molecular clusters to reduce repulsion with O atom. These results demonstrate that the formation of these low-lying isomers is determined by the delicate balance between ion-water and water-water interactions.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Engineering, Chemical
Zhonglin Dong, Tao Jiang, Bin Xu, Hong Zhong, Bangsheng Zhang, Guiqing Liu, Qian Li, Yongbin Yang
Summary: The electronic structure and flotation properties of tetrahedrite were systematically studied in relation to four typical natural impurities using density functional theory. It was found that iron impurity increases the difficulty of tetrahedrite's separation from other sulfides, while zinc, arsenic, and silver impurities have varying effects on the flotation properties of tetrahedrite.
MINERALS ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Yixiao Chen, Linfeng Zhang, Han Wang, E. Weinan
Summary: DeePKS-kit is an open-source software package for developing machine learning based energy and density functional models. It supports multiple methods and provides simple and customized tools. The paper also provides an example of developing a chemically accurate model for water clusters.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Chao Gu, Ziyu Lyu, Qin Hu, Yanping Bao
Summary: In this study, the structural and mechanical properties of Ca-SiO2 compounds in liquid steels were investigated using first-principles density functional theory. Eight different phases were identified and their stability and properties were determined. The results provide valuable insights into the Ca-SiO2 compound particles in steels and contribute to the development of a corresponding property database.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2023)
Review
Chemistry, Physical
Aaron D. Kaplan, Mel Levy, John P. Perdew
Summary: Ground-state Kohn-Sham density functional theory provides the exact ground-state energy and electronic spin densities of interacting electrons in an external potential. Approximations for the exchange-correlation energy are necessary in practice. This work reviews known mathematical properties of the exact exchange-correlation functional and discusses the implications for density functional approximations. The study suggests that more accurate constraints and fitting to bonded systems can improve the predictive power of functionals.
ANNUAL REVIEW OF PHYSICAL CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Juanli Zhao, Peiying Wang, Yuchen Liu, Bin Liu, Haixuan Xu
Summary: This study systematically investigated the electronic structures, mechanical and optical properties of the organo-inorganic hybrid perovskite CH3NH3PbI3 in different crystal structures. The results indicate significant effects of crystal structure and CH3NH3 molecular orientation on the material properties.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Sajanthan Sekaran, Masahisa Tsuchiizu, Matthieu Saubanere, Emmanuel Fromager
Summary: Quantum embedding based on reduced density matrices is re-examined using unitary Householder transformations, leading to the development of Ht-DMFET. This method preserves the single-particle character of the bath and produces accurate results for energy matching, particularly in the noninteracting case. Further exploration of connections with density/density matrix functional theories is ongoing.
Article
Chemistry, Physical
Ming -Zhu Liu, Xiao-Hong Li, Xing-Hao Cui, Hai-Tao Yan, Rui-Zhou Zhang, Hong -Ling Cui
Summary: Density functional theory was used to investigate the electronic properties, optical properties, and quantum capacitance of bare and functionalized Hf2C and Hf2CT2 MXenes. The introduction of functional groups can improve the stability of the system and modulate its properties and capacitance. The results of this study are important for the design and synthesis of new electrode materials.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Jiawei Chang, Qiuyuan Chen, Lin Ma, Chenghan Li, Yicheng Peng, Wei Wu, Hai Wang
Summary: In this study, the electronic structure and magnetic properties of CaCrO3 were calculated using the PBE0 method, revealing a G-type antiferromagnetic ground state with some ferromagnetic characteristics.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Yusuf Zuntu Abdullahi, Abdullahi Lawal, Thong Leng Lim, Sohail Ahmad
Summary: The ground state properties of RuTe2 sheet were studied under different external factors, atomic substitutional doping, and chemical functionalization using density functional theory (DFT) and DFT+Hubbard U. It was found that while RuTe2 and RuSTe sheets exhibit nonmagnetic semiconducting properties, Mn-RuTe2 sheet shows ferromagnetic metal characteristics. The band-gap of RuTe2 sheet can be tuned under applied mechanical strain, and the Janus RuSTe sheet improves carrier mobility compared to RuTe2 sheet.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Physics, Condensed Matter
Shina Li, Hao Quan, Xin Ju
Summary: The study reveals that I/4mmm-FeH5 exhibits good mechanical stability between 100 GPa and 300 GPa, with metallic properties and ionic bond formation under pressure. The elastic moduli show a monotonic increase with pressure.
SOLID STATE COMMUNICATIONS
(2021)
Article
Engineering, Chemical
Jianxiong Kang, Yanni An, Jiwei Xue, Xiao Ma, Jiuzhou Li, Fanfan Chen, Sen Wang, He Wan, Chonghui Zhang, Xianzhong Bu
Summary: The electronic structure of the galena surface was investigated using first-principle calculation. The results showed that galena is a p-type semiconductor with a direct band gap. During the formation of galena, the 3p orbital of S and the 6p orbital of Pb played a primary role. Additionally, the surface properties of galena were influenced by the transfer of electrons from the 6p orbital of Pb to the 3p orbital of S.
Article
Computer Science, Artificial Intelligence
Johannes Gedeon, Jonathan Schmidt, Matthew J. P. Hodgson, Jack Wetherell, Carlos L. Benavides-Riveros, Miguel A. L. Marques
Summary: This article presents a solution to the problems in density functional theory, namely the explicit dependency of the functionals on the particle number and the derivative discontinuity at integer particle numbers. They propose training a neural network as a universal functional that exhibits piece-wise linearity between integer particle numbers and reproduces the derivative discontinuity of the exchange-correlation energy.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Jing Yang, Stefano Falletta, Alfredo Pasquarello
Summary: We present an efficient procedure for constructing nonempirical hybrid functionals to accurately predict band gaps of extended systems. By enforcing the generalized Koopmans'condition on localized electron states and inserting an optimized potential probe, we determine the mixing parameters and achieve band gaps with a mean error of 0.30 eV with respect to experiment. We also propose a perturbative one-shot approach to calculate single-particle eigenvalues, which reduces the computational cost by approximately 85% without loss of accuracy.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Materials Science, Multidisciplinary
M. Naveed-Ul-Haq, Gul-e-Ali
Summary: This study investigates the elastic, electronic, and magnetic properties of orthorhombic niobates containing magnetic transition ions (Mn, Fe, Co, and Ni). The results show that these compounds have promising potential for applications in energy storage, electro-photoactivity, and low-dimensional magnetic character. The study provides a comprehensive theoretical investigation of the materials properties, enabling researchers to tailor their properties according to specific application requirements.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Zhi Li, Ming Yue, Xubo Liu, Hongguo Zhang, Weiqiang Liu, Yuqing Li, Zhipeng Zhang
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2020)
Article
Engineering, Electrical & Electronic
X. B. Liu, M. S. Kesler, M. F. Besser, M. J. Kramer, M. A. McGuire, I. C. Nlebedim
Summary: High coercivity and anisotropic Nd-Fe-B powders for anisotropic bonded magnets were prepared by hydrogenation-disproportionation-desorption-recombination (HDDR) method. The processing hydrogen pressure is closely related to the formation of c-axis crystal texture of Nd2Fe14B phase, with a critical hydrogen pressure, P-crit, promoting the formation of c-axis texture. The existence of P-crit is attributed to the thermodynamics and kinetics during HDDR process.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Engineering, Electrical & Electronic
X. B. Liu, Ikenna C. Nlebedim, Zaven Altounian
Summary: By partially replacing Ce with Nd and/or Pr, the performance of Ce-Fe-B magnets can be improved, with the distribution of Nd/Pr playing a key role in the microstructure. Optimizing magnetic properties can be achieved by manipulating the distribution profile of chemical elements based on their subtle differences in thermodynamic properties.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Physics, Applied
X. B. Liu, Kinjal Gandha, I. C. Nlebedim, M. Parans Paranthaman
Summary: The alignment of magnetic powder in anisotropic bonded magnets is influenced by the filling fraction, binder type, and processing parameters. A good alignment can be achieved through an alignment magnetic field that is approximately twice its coercivity.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Baozhi Cui, Xubo Liu, Cajetan I. Nlebedim, Jun Cui
Summary: Samarium-cobalt sintered magnets exhibit excellent magnetic properties, thermal stability, and corrosion resistance, but their brittleness limits their applications. This paper presents a novel approach to improve the mechanical resilience of the magnets by engineering heterogeneous microstructures, resulting in increased flexural strength without significant impact on their magnetic properties. The developed technology is compatible with existing magnet manufacturing processes and can be readily adopted by the magnet industry.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Ceramics
Kinjal Gandha, Mariappan Parans Paranthaman, Haobo Wang, Xubo Liu, Ikenna C. Nlebedim
Summary: This research demonstrates the additive printing of anisotropic NdFeB + SmFeN and NdFeB bonded magnets with excellent magnetic properties, corrosion resistance, and thermal stability.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
A. Thayer, I Hlova, Y. Mudryk, X. Liu, V. K. Pecharsky
Summary: Single-phase LaFe13-x-yMxSiyN3 compounds were synthesized by ammonia flow, exhibiting increased lattice expansion and magnetic ordering transitions as a result of nitrogenation. The nitrides show weak and broad magnetocaloric effects, and stability below 750 K but decompose above this temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Baozhi Cui, Xubo Liu, I. C. Nlebedim, Jun Cui
Summary: Samarium-cobalt (Sm-Co) sintered magnets have excellent magnetic properties and thermal stability, but their brittleness limits their applications. By incorporating a small amount of Sm2O3 particles, the mechanical properties of these magnets can be improved. The addition of Sm2O3 refines the grain size and enhances the flexural strength of the magnets, while remaining compatible with existing manufacturing processes.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Baozhi Cui, Xubo Liu, I. C. Nlebedim, Jun Cui
Summary: This study reports the modified microstructure, refined grain size, enhanced flexural strength, and magnetic properties of La2O3, MgO, and CaF2-doped Sm2(Co, Fe,Cu,Zr)17 sintered magnets. The correlations between microstructure, phase composition, and mechanical and magnetic properties were studied. Doping a small amount of La2O3, MgO, or CaF2 significantly refined the grain size and improved the flexural strength of the magnets. The rational design of CaF2- or La2O3-doped microstructure can be an economical and effective method for producing toughened Sm-Co sintered magnets with high magnetic performance.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Wei Tang, Gaoyuan Ouyang, Xubo Liu, Jing Wang, Baozhi Cui, Jun Cui
Summary: The study finds that by introducing a non-magnetic grain boundary phase, the loss of coercivity in MnBi magnets can be significantly reduced, leading to improved performance.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
X. B. Liu, I. C. Nlebedim
Summary: Critical La2Fe14B compound has the potential to be a gap permanent magnet, but it decomposes below 1067 K. The stability and coercivity of La2Fe14B magnet have been studied using DFT calculation and micromagnetic simulation. The addition of a thin layer of alpha-Fe reduces the coercivity sharply, and partial replacement of La by other rare-earth elements can enhance the structural stability.
Article
Nanoscience & Nanotechnology
X. B. Liu, D. H. Ryan, Z. Altounian
Summary: The phase stability and magnetocrystalline anisotropy (MCA) of tetragonal Mn(Al1-xGax) with the L1(0)-type structure (P4/mmm) were investigated using first-principles density functional calculations. The results showed that replacing Al with Ga suppressed the formation of Mn-5(Al,Ga)(8) and improved the thermal stability of the L1(0) phase without significant changes in the total magnetic moment. The MCA was mainly contributed by Mn atoms and increased from 0.25 meV/f.u. (x = 0) to 0.34 meV/f.u. (x = 1). Doping with Ga enhanced the thermal stability of the L1(0) structure and increased the effective magnetic anisotropy field.
Article
Chemistry, Physical
Jeotikanta Mohapatra, Xubo Liu, Pramanand Joshi, J. Ping Liu
Summary: Iron (Fe) is an important ferromagnetic element with high magnetic moment and Curie temperature, and it is widely used in technologies and industries. While Fe-based materials are mostly used as soft magnetic materials due to low magneto-crystalline anisotropy (MCA), recent research has shown promising evidence for achieving high MCA in Fe-based hard magnetic materials without rare-earth elements. This paper reviews the history and recent developments of Fe-based hard and semi-hard magnetic materials, focusing on the mechanisms of high MCA and the related crystal and electronic structures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Multidisciplinary
Xubo B. Liu, Kinjal Gandha, Haobo Wang, Kaustubh Mungale, Uday Kumar Vaidya, Ikenna C. Nlebedim, Mariappan Parans Paranthaman
Summary: Highly dense and magnetically anisotropic rare earth bonded magnets were fabricated using a batch extrusion process and compression molding technology. The magnets had a mixture of Sm-Fe-N and Nd-Fe-B particles with a polyphenylene sulfide binder. The hybrid bonded magnet had a high density and a maximum energy product, with the fine-sized Sm-Fe-N particles filling the gap between the larger Nd-Fe-B particles.
Article
Materials Science, Multidisciplinary
Harshida Parmar, Xubo Liu, Kinjal Gandha, M. Parans Paranthaman, Ikenna C. Nlebedim
Summary: This study investigates the effect of magnetic field annealing on relieving the stress induced during milling of Nd-Fe-B sintered magnets, and explores the influence of MA processing parameters and particle size on the magnetic properties. The results demonstrate that magnetic field annealing is more effective in improving the magnetic properties of larger particles compared to finer particles. Computational study supports the role of particle surface defects in bimodal particle distribution seen experimentally. Magnetic field annealed powder has been used successfully to develop bonded magnets with a density of 4.6 g.cm 3, consisting of 75% magnetic powder and polyamide 12 (nylon 12) polymer binder, resulting in an energy product of 11.3 MGOe.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
