Article
Physics, Condensed Matter
V. H. Tran, M. Sahakyan, Z. Bukowski
Summary: A crystalline sample YGa2 with the AlB2-type hexagonal structure was synthesized using the self-flux method. Experimental measurements showed type-II superconductivity in the sample, with the unusual behavior of temperature dependence of the upper critical field H(c2)(T(c)) attributed to crystal twinning. DFT calculations indicated a significant change in the Fermi velocity of carriers near the cylinder-like structured Fermi surface along the Gamma - A line.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Materials Science, Ceramics
V. I. Ivashchenko, P. E. A. Turchi, R. Shevchenko, Leonid Gorb, Jerzy Leszczynski
Summary: First-principles molecular dynamics simulations were used to generate samples of amorphous a-AlB2, a-AlBC, and a-AlBN alloys, which exhibited boron clustering and different structural characteristics. The phonon spectra of the amorphous samples displayed broad bands, while the alloys varied in hardness, ideal tensile strength, Debye temperature, and fracture toughness. Predictions suggest that crystalline AlB2 is closer to a brittle material, while the amorphous alloys are expected to exhibit ductile behavior and semiconductor properties with a mobility gap in a certain range.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Materials Science, Multidisciplinary
Jiasheng Ji, Hengyong Bu, Yonghua Duan, Mingjun Peng, Huarong Qi, Xiaoqi Wang, Li Shen
Summary: In this study, the structural, electrical, elastic, and thermal properties of TM5Si3N (TM = V, Nb, and Ta) Nowotny phase were investigated using first-principles calculations. The results indicate that TM5Si3N Nowotny phases are dynamically and thermodynamically stable. The TM5Si3N compound forms strong TM-Si and TM-N bonds due to the hybridization between TM-d state and Si-p and N-p states. The elastic modulus and thermal conductivity of TM5Si3N were found to be anisotropic with different magnitudes for different elements.
Article
Materials Science, Multidisciplinary
K. Mopoung, A. Ektarawong, T. Pakornchote, E. Johansson, B. Alling
Summary: This study examines the thermodynamic stability and elastic properties of ScB2-VB2 mixtures with the AlB2-type structure, which have potential as hard coatings. The research combines the cluster-expansion method and first-principles calculations to predict the behavior of the mixtures at low temperatures. The results indicate that Sc and V atoms tend to be surrounded by atoms of the opposite type, allowing for the fabrication of Sc1-XVXB2 in the form of superlattices. Interestingly, the stiffness, shear strength, and hardness of Sc1-XVXB2 deviate from Vegard's law, suggesting that the electronic band filling plays a role in their properties.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Multidisciplinary Sciences
Kunpot Mopoung, Annop Ektarawong, Thiti Bovornratanaraks, Bjorn Alling
Summary: In this study, the mixing thermodynamics and mechanical properties of AlB2-structured Sc1-xTaXB2 solid solutions were investigated using first-principles calculations. The results showed that TaB2 and ScB2 readily mix to form a continuous series of stable solid solutions, with significant positive deviations in the elastic moduli and hardness compared to the linear Vegard's rule. The improved stability and mechanical properties of Sc1-xTaXB2 solid solutions were attributed to the effect of electronic band filling induced by mixing TaB2 with ScB2.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Ceramics
Ze Zhang, Shizhen Zhua, Yanbo Liu, Ling Liu, Zhuang Ma
Summary: In this study, six quaternary and quinary high-entropy transition metal and rare-earth diborides (HE TMREB2) were designed and their phase stability and properties were investigated. The results show that the addition of REB2 has a significant impact on the phase stability and thermal properties.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Xiang-Gui Li, Jian-Guo Si, Lan-Ting Shi, Peng-Fei Liu, Ping Zhang, Bao-Tian Wang
Summary: In this study, the stability, mechanical properties, superconductivity, electronic structures, and topological states of hexagonal TaC and NbC were systematically investigated using first-principles calculations. The results show that these materials are stable, have excellent mechanical properties, and exhibit strong electron-phonon coupling superconductivity and topological states. They are potential candidates for topological superconductors.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Xun Ge, Xiaohao Zhou, Deyan Sun, Xiaoshuang Chen
Summary: The structural parameters and electronic properties of PTX2 and Janus PtXY were studied using density functional theory. The results showed that these monolayers are stable and highly flexible materials with outstanding stretchability. The electronic properties of these materials can be modulated by applying compressive or tensile strain, and a transition from indirect to quasi-direct semiconductor was observed under tensile strain.
Article
Chemistry, Multidisciplinary
Qingyang Fan, Ruida Zhao, Yingbo Zhao, Yanxing Song, Sining Yun
Summary: In this study, eight BN polymorphs (2H, 4H, 5H, 6H-I, 6H-II, 7H-I, 7H-II, and 7H-III) were obtained using a random sampling strategy, and their similarities to 3C BN in stacking order were observed. The calculations showed that these polymorphs have high stability and thermal stability. Additionally, they exhibit superhard characteristics and can be considered as promising ultrawide-bandgap semiconductors.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
Zisheng Zhang, Ive Hermans, Anastassia N. Alexandrova
Summary: Boron-containing materials, such as h-BN, have been found to be active and selective catalysts for ODHP. This study explores the restructuring of the h-BN surface under ambient and ODHP-relevant conditions using a global optimization structure search algorithm. The results show that the sliding of h-BN sheets significantly strains the B-O linkages on the edges, increasing the reactivity towards propane and water activation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Green & Sustainable Science & Technology
Yingliang Zhao, Yong Sun, Zhenbang Guo, Jingping Qiu, Xiaogang Sun
Summary: Hazardous wastes are often immobilized using cementitious materials. Ettringite is a potential material for stabilizing arsenate in cementitious waste streams. This study investigated the effects of As(V) doping into the ettringite structure using first-principles calculations, and found that As doping increased the stability of ettringite and its mechanical properties.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Chemistry, Multidisciplinary
Soon-Dong Park, Sung Youb Kim
Summary: In this study, we used spin-polarized density functional theory to analyze the properties of the Cr(001)/Al(001) structure, and found that the interface can be classified into three forms: bcc, bridge, and top. The total density of states of the structures is mainly influenced by the Cr (d) orbitals. The analysis of the mechanical properties showed that deformation mainly occurs in the Al region regardless of the interface type.
Article
Materials Science, Multidisciplinary
S. B. Song, Z. Wang, J. Li, R. Q. Wu
Summary: Through density-functional calculations, the exchange bias effect of the antiferromagnetic Cr(001) substrate on a single magnetic molecule CoCp2 has been systematically studied. The magnetic moment and magnetic anisotropy of CoCp2 can be greatly tuned by the charge transfer between the molecule and substrate. A large exchange energy of approximately 94 meV has been found, which essentially pins the spin orientation of CoCp2. This makes CoCp2/Cr(001) an ideal combination for quantum sensing with well-decoupled quantum spin states from the target magnetic entities.
Article
Materials Science, Multidisciplinary
Davide Gambino, Johan Klarbring, Bjorn Alling
Summary: This work demonstrates the feasibility and accuracy of calculating phase stability in magnetic systems using ab initio methods and thermodynamic integration. By sampling the magnetic and vibrational phase space with coupled atomistic spin dynamics-ab initio molecular dynamics simulations, energies and interatomic forces are calculated with density functional theory. The method is applied to calculate the phase stability of Fe at ambient pressure from 800 to 1800 K. The Gibbs free energy difference between fcc and bcc Fe is calculated with thermodynamic integration, and the error in transition temperature is below 150 K, with a difference of 5 meV/atom from the CALPHAD estimate. This work lays the foundation for first principles free energy calculations in magnetic materials with accuracy on the order of 1 meV/atom.
Article
Materials Science, Multidisciplinary
Cheng Tang, Lei Zhang, Yalong Jiao, Chunmei Zhang, Stefano Sanvito, Aijun Du
Summary: By combining particle swarm optimization with first-principles calculations, a stable 2D polar half-metal, quintuple layered Co2Se3 monolayer, has been predicted. This material exhibits XY magnetism and out-of-plane piezoelectricity, showing multiferroic properties and great potential in advanced multiferroic applications.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Physics, Applied
D. V. Suetin, I. R. Shein
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
(2018)
Article
Chemistry, Inorganic & Nuclear
Aleksei G. Krasnov, Mania S. Koroleva, Maxim Vlasov, Igor R. Shein, Irina Piir, Dina G. Kellerman
INORGANIC CHEMISTRY
(2019)
Article
Chemistry, Physical
A. G. Krasnov, A. A. Kabanov, N. A. Kabanova, I. V. Piir, I. R. Shein
SOLID STATE IONICS
(2019)
Article
Chemistry, Physical
V. P. Zhukov, B. Politov, A. Yu Suntsov, I. A. Leonidov, I. R. Shein, V. L. Kozhevnikov
SOLID STATE IONICS
(2020)
Article
Chemistry, Inorganic & Nuclear
Aleksei G. Krasnov, Maxim S. Napalkov, Maxim Vlasov, Mariia S. Koroleva, Igor R. Shein, Irina Piir
INORGANIC CHEMISTRY
(2020)
Article
Chemistry, Physical
M. S. Koroleva, A. G. Krasnov, A. Senyshyn, A. Schoekel, I. R. Shein, M. Vlasov, I. Piir
Summary: Experimental and theoretical investigations were conducted on novel bismuth niobates with pyrochlore structure, showing the effects of Na and Mg doping on their crystal structure, thermal stability, and electrical properties. The results indicated that the band gap values and electrical properties of the compounds were influenced by the concentrations of Na and Mg dopants in the structure.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Mariia S. Koroleva, Aleksei G. Krasnov, Anatoliy Senyshyn, Alexander Schoekel, Igor R. Shein, Maxim Vlasov, Irina Piir
Summary: New pyrochlore-structured compounds Bi1.5Mg0.9-xLixNb1.5O7-delta (x = 0.25; 0.40) and Bi1.4RE0.1Mg0.5Li0.4Nb1.5O7-delta (RE - Eu, Ho, Yb) were synthesized and their atomic displacements and dopant distribution were studied. The preferred model with a direct band gap of 3.18 eV was predicted, and the thermal stability of the compounds was determined. Charge disbalance and oxygen vacancies were found to affect the dielectric behavior and conductivity of the ceramics.
MATERIALS RESEARCH BULLETIN
(2022)
Article
Chemistry, Physical
A. G. Krasnov, M. S. Koroleva, I. Piir, I. R. Shein
Summary: A detailed study combining density functional theory (DFT) and experiments was conducted on the substitution of Li and Na in Bi2Ti2O7 pyrochlore (BTO). The study showed that Na-doped BTO pyrochlores can only be obtained at low sodium content, while Li-doped BTOs can be synthesized at various lithium content. The doped pyrochlore compositions were found to be wide-band indirect semiconductor materials with good conductivity. The experimental results confirmed the predictions from the DFT simulations.
SOLID STATE IONICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Mariia S. Koroleva, Aleksey V. Ishchenko, Maxim I. Vlasov, Aleksei G. Krasnov, Elena I. Istomina, Igor R. Shein, Ilya A. Weinstein, Irina V. Piir
Summary: Eu-doped bismuth-based pyrochlore ceramics were synthesized using the organic-inorganic precursor combustion technique. The study investigated the effect of Eu3+ doping on the structural, dielectric, optical, and luminescence properties, and found that Eu3+ doping caused structural distortion and decreased dielectric permittivity. Additionally, the study also demonstrated the influence of Li and Na content, additional phases, and dopant concentration on the material properties.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Natalia V. Chezhina, Irina V. Piir, Aleksei G. Krasnov, Mariia S. Koroleva, Dina G. Kellerman, Valentin G. Semenov, Elizaveta V. Shalaeva, Ivan I. Leonidov, Igor R. Shein
Summary: The nanoparticles of pyrochlore Bi1.5Fe0.5Ti2O7-delta were prepared and characterized using various techniques. The distribution and behavior of Fe atoms in the nanosized Bi1.5Fe0.5Ti2O7-delta were investigated. The study showed that the local microstructure of the metastable nanosized sample determined the local distribution, electronic structure, and magnetic behavior of Bi1.5Fe0.5Ti2O7-delta.
INORGANIC CHEMISTRY
(2022)
Article
Physics, Multidisciplinary
N. S. Pavlov, I. R. Shein, K. S. Pervakov, I. A. Nekrasov
Summary: A comparative analysis of electronic structures of possible isostructural analogues of iron superconductors InCo2As2 and KInCo4As4 with BaFe2As2 was conducted using DFT/LDA and LDA + DMFT approaches. Results showed relatively small quasiparticle mass renormalization at the Fermi level, and significant shifts and compressions of the spectrum below -0.8 eV due to correlation effects. The band structure of InCo2As2 resembled BaCo2As2, while KInCo4As4 showed similarities with the band structure and Fermi surfaces of BaFe2As2, suggesting the possibility of superconductivity. Furthermore, LDA + DMFT calculations indicated topological Lifshitz transitions under hole or electron doping in KInCo4As4. The synthesis of InCo2As2 and KInCo4As4 compounds is crucial for studying superconductivity in this class of materials.
Article
Chemistry, Inorganic & Nuclear
I. R. Shein
Summary: In this study, the electronic structures and chemical bonding parameters of Th-B systems (ThB4, ThB6, and ThB12 structures) were investigated using ab initio methods and considering relativistic effects. The behavior of formation energy in relation to the partial content of boron was also examined.
JOURNAL OF STRUCTURAL CHEMISTRY
(2022)
Article
Chemistry, Physical
B. V. Politov, J. C. Waerenborgh, I. R. Shein, O. V. Merkulov
Summary: The crystalline and electronic band structures, thermodynamic stability, oxygen non-stoichiometry and high-temperature transport properties of perovskite-like solid solutions Sr1-yFe0.5-xTa0.5+xO3-delta have been thoroughly studied. It is found that intentionally introducing defects in the strontium sublattice can stabilize the oxides with excess tantalum content. The charge states in the iron sublattice are mainly Fe3+ ions, and the band structure calculations support the semiconducting nature of electrical transport. The overall defect structure heavily relies on oxygen vacancy formation processes. Increasing the tantalum content improves the oxygen non-stoichiometry and conductive properties of the materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
I. R. Shein, V. V. Novikov, S. Kuznetsov, K. Ponkratov, A. Matovnikov, N. Mitroshenkov, B. Kornev, A. Morozov, V. L. Prishchep, S. L. Bud'ko
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2019)
Article
Physics, Condensed Matter
V. V. Bannikov, I. R. Shein
COMPUTATIONAL CONDENSED MATTER
(2018)