The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Dongfeng Xue - One of the best experts on this subject based on the ideXlab platform.
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chemical bonding theory of Single Crystal Growth and its application to Crystal Growth and design
CrystEngComm, 2016Co-Authors: C Sun, Dongfeng XueAbstract:The effects of Crystallization on the formation of geochemical, biological, and synthetic materials have been motivating decades of research into Crystal nucleation and Growth processes. The development of Crystal Growth theories and models can deepen the understanding of physicochemical interactions during the Crystal Growth process, which facilitates the designing of Crystallization approaches in material production. The chemical bonding theory of Single Crystal Growth emphasizes the dominant role of dynamic chemical bonding mechanisms at the growing interfaces. In this paper, we highlight the chemical bonding theory of Single Crystal Growth from the chemical reaction viewpoint, by focusing on the atomic level of the growing interface between the liquid and Crystal phases. Using ZnO, CeO2, MnO2 and Y3Al5O12 as examples, we review some typical applications of the chemical bonding theory of Single Crystal Growth in calculating Crystal habits, evaluating Crystal properties, and guiding practical Single Crystal Growth. Microscopically speaking, the essence of Crystal Growth and design is to create ideal chemical bonding architectures at both the Crystal surface and the growing interface via both thermodynamic and kinetic strategies.
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applying the chemical bonding theory of Single Crystal Growth to a gd3ga5o12 czochralski Growth system both thermodynamic and kinetic controls of the mesoscale process during Single Crystal Growth
CrystEngComm, 2015Co-Authors: Yan Wang, C Sun, Dongfeng XueAbstract:The chemical bonding theory of Single Crystal Growth was applied to a Gd3Ga5O12 (GGG) Czochralski Growth system. On the basis of anisotropic chemical bonding characteristics, the mesoscale process controlled by both thermodynamics and kinetics has been studied in GGG Single Crystal Growth. Starting from the unit-scale in the Growth system, the mesoscale structures undergo evolution from GdO8, GaO6, and GaO4 to Gd3Ga5O12 clusters and to a GGG Single Crystal via chemical bonding between Gd, Ga, and O. On the basis of the chemical bonding theory of Single Crystals, the GGG Single Crystal thermodynamically prefers to exhibit a hexagonal configuration along the [111] pulling direction. Kinetically, isotropic mass transfer in the Czochralski Growth process leads to formation of a GGG Single Crystal with a circular configuration, as viewed down along the [111] direction. In such a case, the GGG Single Crystal maintains the lowest energy. In order to satisfy both thermodynamic and kinetic controls, the thermodynamically preferred {−110} microfacets are exposed on the microscale and the Single Crystal adopts a circular shape on the macroscale. The present work deepens our understanding of the mesoscale process in the GGG Czochralski Growth system.
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chemical bonding theory of Single Crystal Growth and its application to ϕ 3 yag bulk Crystal
CrystEngComm, 2014Co-Authors: C Sun, Dongfeng XueAbstract:The Growth of YAG bulk Crystals was studied using both theoretical calculations based on the anisotropic chemical bonding conditions and practical Growth via the Czochralski (Cz) method. The chemical bonding theory of Single Crystal Growth quantitatively describes the anisotropic bonding behaviors of constituent atoms during Crystallizing, which can be applied to the thermodynamic Growth of YAG Single Crystals. Both bonding conditions and Crystal symmetry determine the projection configuration along the pulling direction and Crystal ridges in the Crystal shoulder of YAG grown along [111] direction. During Cz Growth process of YAG Single Crystals, the relative low Growth rate along directions results in the exposure of surfaces normal to directions. However, the chemical bonding energy density at the intersection of two adjacent Growth directions is higher, leading to the exposure of surfaces normal to directions and the truncated-hexagon configuration of YAG along [111] direction. ϕ 3′′ YAG Single Crystal was successfully grown. Our present work provides a promising approach to achieve controllable Growth for functional bulk Crystal via both thermodynamic and kinetic controls.
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evolution of interface configuration in sapphire Single Crystal Growth via czochralski method
Materials Research Innovations, 2013Co-Authors: C T Sun, Dongfeng XueAbstract:The evolution of interface configuration during sapphire Crystal Growth by Czochralski method was studied on the basis of chemical bonding conditions at Crystal/melt interface. On the basis of chemical bonding theory of Single Crystal Growth, when sapphire Single Crystal was grown along the c axis direction in Czochralski system, Crystal/metal interface is composed of six Crystallographically equivalent {110} interfaces thermodynamically. With the rotation of sapphire Single Crystal in the Growth process, the interface configuration developed from hexagon to circle due to the appearance of {100} surfaces and {h10} microfacets at the intersection of two adjacent interfaces. The (h10) microfacet is made of (100) and (110) planes. Lower chemical bonding densities at the {100} surfaces and {h10} microfacets relative to that at {110} surfaces thermodynamically drive the formation of round interface configuration in sapphire Czochralski Crystal Growth along the c axis direction.
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chemical bond simulation of kadp Single Crystal Growth
Journal of Crystal Growth, 2008Co-Authors: Dongfeng XueAbstract:Abstract The mixed Crystals of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) with different Growth morphologies have been prepared and investigated by X-ray diffraction experiments. All the obtained samples Crystallize in the tetragonal system with a continuous expansion of unit cell when increasing ammonium content. The different characteristics of potassium and ammonium lead to the deformation of Crystal structure, production of internal stress and degradation of the obtained Crystal quality. When ammonium or potassium content in the mixed Crystal is low, the accumulated internal stress is weaker and the mixed Crystals with high quality can be grown. Contrarily, in the intermediate composition, especially around 65 percent ammonium, the strongest internal stress results in the intensive distortion of Crystal lattice and consequent cracks within the mixed Crystals. The microscopic mechanism of the morphology evolution of the mixed Crystals is proposed and calculated in the chemical bond viewpoint and bond valence model, the difference of the average valence electron density between the KDP and ADP dominates their different Growth morphologies.
Yuheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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Single Crystal Growth of the new pressure induced superconductor cras via chemical vapor transport
Journal of Alloys and Compounds, 2016Co-Authors: Xiangde Zhu, Changjin Zhang, Langsheng Ling, Yuyan Han, Y J Wang, Hongwei Zhang, Yuheng ZhangAbstract:Abstract Mono-arsenide CrAs, endures a helical anti-ferromagnetic order transition at ∼265 K under ambient pressure. Recently, pressure-induced-superconductivity was discovered vicinity to the helical anti-ferromagnetic order in CrAs [Wei Wu et al., Nature Communications 5, 5508 (2014).]. However, the size of Crystal grown via tin flux method is as small as 1 mm in longest dimension. In this work, we report the Single Crystal Growth of CrAs with size of 1 × 5 × 1 mm 3 via chemical vapor transport method and its physical properties.
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Single Crystal Growth transport and electronic band structure of ycoga5
Journal of Alloys and Compounds, 2013Co-Authors: Wenjian Lu, Wei Ning, Zhe Qu, Li Li, T F Qi, C Petrovic, Yuheng ZhangAbstract:Abstract Single Crystal of YCoGa5 has been grown via Ga self-flux. In this paper, we report the Single Crystal Growth, Crystallographic parameters, resistivity, heat capacity, and band structure results of YCoGa5. YCoGa5 accommodates the HoCoGa5 type structure (space group P4/mmm (No. 123), Z = 1, a = 4.2131(6) A, c = 6.7929(13) A, which is isostructural to the extensively studied heavy fermion superconductor system CeMIn5 (M = Co, Rh, Ir) and the unconventional superconductor PuCoGa5 with Tc = 18.5 K. No superconductivity is observed down to 1.75 K. Band structure calculation results show that its band at the Fermi level is mainly composed of Co-3d and Ga-4p electrons states, which explains its similarity of physical properties to YbCoGa5 and LuCoGa5.
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Single Crystal Growth transport and electronic band structure of ycoga5
ChemInform, 2013Co-Authors: Wenjian Lu, Wei Ning, Zhe Qu, Li Li, T F Qi, C Petrovic, Yuheng ZhangAbstract:Single Crystals of YCoGa5 are prepared from mixtures of the elements using a large excess of Ga as a flux (1100 °C, 6 h).
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Single Crystal Growth of bafe _ 2 x co _x as _2 without fluxing agent
arXiv: Superconductivity, 2010Co-Authors: Changjin Zhang, Lei Zhang, Langsheng Ling, Shun Tan, Yuheng ZhangAbstract:We report a simple, reliable method to grow high quality BaFe$_{2-x}$Co$_x$As$_2$ Single Crystal samples without using any fluxing agent. The starting materials for the Single Crystal Growth come from well-Crystallized polyCrystalline samples and the highest growing temperature can be 1493 K. The as-grown Crystals have typical dimensions of 4$\times3\times$0.5 mm$^3$ with c-axis perpendicular to the shining surface. We find that the samples have very large current carrying ability, indicating that the samples have good potential technological applications.
C Sun - One of the best experts on this subject based on the ideXlab platform.
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chemical bonding theory of Single Crystal Growth and its application to Crystal Growth and design
CrystEngComm, 2016Co-Authors: C Sun, Dongfeng XueAbstract:The effects of Crystallization on the formation of geochemical, biological, and synthetic materials have been motivating decades of research into Crystal nucleation and Growth processes. The development of Crystal Growth theories and models can deepen the understanding of physicochemical interactions during the Crystal Growth process, which facilitates the designing of Crystallization approaches in material production. The chemical bonding theory of Single Crystal Growth emphasizes the dominant role of dynamic chemical bonding mechanisms at the growing interfaces. In this paper, we highlight the chemical bonding theory of Single Crystal Growth from the chemical reaction viewpoint, by focusing on the atomic level of the growing interface between the liquid and Crystal phases. Using ZnO, CeO2, MnO2 and Y3Al5O12 as examples, we review some typical applications of the chemical bonding theory of Single Crystal Growth in calculating Crystal habits, evaluating Crystal properties, and guiding practical Single Crystal Growth. Microscopically speaking, the essence of Crystal Growth and design is to create ideal chemical bonding architectures at both the Crystal surface and the growing interface via both thermodynamic and kinetic strategies.
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applying the chemical bonding theory of Single Crystal Growth to a gd3ga5o12 czochralski Growth system both thermodynamic and kinetic controls of the mesoscale process during Single Crystal Growth
CrystEngComm, 2015Co-Authors: Yan Wang, C Sun, Dongfeng XueAbstract:The chemical bonding theory of Single Crystal Growth was applied to a Gd3Ga5O12 (GGG) Czochralski Growth system. On the basis of anisotropic chemical bonding characteristics, the mesoscale process controlled by both thermodynamics and kinetics has been studied in GGG Single Crystal Growth. Starting from the unit-scale in the Growth system, the mesoscale structures undergo evolution from GdO8, GaO6, and GaO4 to Gd3Ga5O12 clusters and to a GGG Single Crystal via chemical bonding between Gd, Ga, and O. On the basis of the chemical bonding theory of Single Crystals, the GGG Single Crystal thermodynamically prefers to exhibit a hexagonal configuration along the [111] pulling direction. Kinetically, isotropic mass transfer in the Czochralski Growth process leads to formation of a GGG Single Crystal with a circular configuration, as viewed down along the [111] direction. In such a case, the GGG Single Crystal maintains the lowest energy. In order to satisfy both thermodynamic and kinetic controls, the thermodynamically preferred {−110} microfacets are exposed on the microscale and the Single Crystal adopts a circular shape on the macroscale. The present work deepens our understanding of the mesoscale process in the GGG Czochralski Growth system.
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chemical bonding theory of Single Crystal Growth and its application to ϕ 3 yag bulk Crystal
CrystEngComm, 2014Co-Authors: C Sun, Dongfeng XueAbstract:The Growth of YAG bulk Crystals was studied using both theoretical calculations based on the anisotropic chemical bonding conditions and practical Growth via the Czochralski (Cz) method. The chemical bonding theory of Single Crystal Growth quantitatively describes the anisotropic bonding behaviors of constituent atoms during Crystallizing, which can be applied to the thermodynamic Growth of YAG Single Crystals. Both bonding conditions and Crystal symmetry determine the projection configuration along the pulling direction and Crystal ridges in the Crystal shoulder of YAG grown along [111] direction. During Cz Growth process of YAG Single Crystals, the relative low Growth rate along directions results in the exposure of surfaces normal to directions. However, the chemical bonding energy density at the intersection of two adjacent Growth directions is higher, leading to the exposure of surfaces normal to directions and the truncated-hexagon configuration of YAG along [111] direction. ϕ 3′′ YAG Single Crystal was successfully grown. Our present work provides a promising approach to achieve controllable Growth for functional bulk Crystal via both thermodynamic and kinetic controls.
R J Cava - One of the best experts on this subject based on the ideXlab platform.
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Crystal Growth structure and magnetism of the 2d spin 1 2 triangular lattice material rb3yb po4 2
Chemistry of Materials, 2020Co-Authors: Shu Guo, Ruidan Zhong, Karolina Gornicka, Tomasz Klimczuk, R J CavaAbstract:The Single-Crystal Growth, Crystal structure, heat capacity, and anisotropic magnetization characterization of Rb3Yb(PO4)2, a Yb-based triangular lattice material, are presented. Single-Crystal X-r...
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Single Crystal Growth and thermoelectric properties of ge bi sb 4te7
Journal of Physics: Condensed Matter, 2013Co-Authors: Andreas Schilling, Fabian O Von Rohr, R J CavaAbstract:The thermoelectric properties between 10 and 300 K and the Growth of Single Crystals of n-type and p-type GeBi(4)Te(7), GeSb(4)Te(7) and Ge(Bi(1-x)Sb(x))(4)Te(7) solid solution are reported. Single Crystals were grown by the modified Bridgman method, and p-type behavior was achieved by the substitution of Bi by Sb in GeBi(4)Te(7). The thermopower in the Ge(Bi(1-x)Sb(x))(4)Te(7) solid solution ranges from -117 to +160 μV K(-1). The crossover from n-type to p-type is continuous with increasing Sb content and is observed at x ≈0.15. The highest thermoelectric efficiencies among the tested n-type and p-type samples are Z(n)T = 0.11 and Z(p)T = 0.20, respectively. For an optimal n-p couple in this alloy system the composite figure of merit is Z(np)T = 0.17 at room temperature.
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Single Crystal Growth and thermoelectric properties of ge bi sb 4te7
arXiv: Materials Science, 2013Co-Authors: Andreas Schilling, Fabian O Von Rohr, R J CavaAbstract:The thermoelectric properties between 10 and 300 K and the Growth of Single Crystals of n-type and p-type GeBi4Te7, GeSb4Te7, and the Ge(Bi1-xSbx)4Te7 solid solution are reported. Single Crystals were grown by the modified Bridgman method, and p-type behavior was achieved by the substitution of Bi by Sb in GeBi4Te7. The thermopower in the Ge(Bi1-xSbx)4Te7 solid solution ranges from -117 muVK^-1 to +160 muVK^-1. The crossover from n-type to p-type is continuous with increasing Sb content and is observed at x = 0.15. The highest thermoelectric efficiencies among the tested n-type and p-type samples are ZnT = 0.11 and ZpT = 0.20, respectively. For an optimal n-p couple in this alloy system the composite figure of merit is ZnpT = 0.17 at room temperature.
Oleg V. Parasyuk - One of the best experts on this subject based on the ideXlab platform.
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tl10hg3cl16 Single Crystal Growth electronic structure and piezoelectric properties
Journal of Solid State Chemistry, 2016Co-Authors: O.yu. Khyzhun, I Luzhnyi, S I Levkovets, M V Karpets, I.v. Kityk, P. Fochuk, A.o. Fedorchuk, Maciej Piasecki, Oleg V. ParasyukAbstract:Abstract Single Crystal of the ternary halide Tl 10 Hg 3 Cl 16 was grown using Bridgman-Stockbarger method. For the Tl 10 Hg 3 Cl 16 Crystal, we have measured X-ray photoelectron spectra for both pristine and Ar + ion-bombarded surfaces and additionally investigated photoinduced piezoelectricity. Our data indicate that the Tl 10 Hg 3 Cl 16 Single Crystal surface is very sensitive with respect to Ar + ion-bombardment. In particular, Ar + ion-bombardment with energy of 3.0 keV over 5 min at an ion current density of 14 μA/cm 2 causes significant changes of the elemental stoichiometry of the Tl 10 Hg 3 Cl 16 surface resulting in an abrupt decrease of the mercury content in the top surface layers of the studied Single Crystal. As a result of the treatment, the mercury content becomes nil in the top surface layers. In addition, the present XPS measurements allow for concluding about very low hygroscopicity of the Tl 10 Hg 3 Cl 16 Single Crystal surface. The property is extremely important for the Crystal handling in optoelectronic or nano-electronic devices working at ambient conditions. The photoinduced piezoelectricity has been explored for Tl 10 Hg 3 Cl 16 depending on nitrogen (λ=371 nm) laser power density and temperature.
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tl10hg3cl16 Single Crystal Growth electronic structure and piezoelectric properties
ChemInform, 2016Co-Authors: O.yu. Khyzhun, I Luzhnyi, S I Levkovets, M V Karpets, I.v. Kityk, P. Fochuk, A.o. Fedorchuk, Maciej Piasecki, Oleg V. ParasyukAbstract:High-quality Single Crystals of Tl10Hg3Cl16 are grown by the Bridgman—Stockbarger method employing TlCl and HgCl2 in the molar ratio of 7:3 (evacuated conical bottom quartz container, 1.