Oleksandr Kurakevych - Academia.edu (original) (raw)
Papers by Oleksandr Kurakevych
Physical Review Letters, Jan 9, 2009
Here, we report the synthesis of cubic BC 5 (c-BC 5), the diamondlike B-C phase with the highest ... more Here, we report the synthesis of cubic BC 5 (c-BC 5), the diamondlike B-C phase with the highest boron content ever achieved, at 24 GPa and about 2200 K, using both a laser-heated diamond anvil cell and large-volume multianvil apparatus. The synthesized phase is low compressible (bulk modulus of 335 GPa), conductive, and exhibits extreme Vickers hardness (71 GPa), unusually high for superhard materials fracture toughness (9:5 MPa m 0:5), and high thermal stability (up to 1900 K); this makes it an exceptional superabrasive and promising material for high-temperature electronics.
Crystal Growth & Design, Oct 8, 2018
Na4Si24 is the precursor to Si24, a recently discovered allotrope of silicon. With a quasidirect ... more Na4Si24 is the precursor to Si24, a recently discovered allotrope of silicon. With a quasidirect band gap near 1.3 eV, Si24 has potential to transform silicon-based optoelectronics including solar energy conversion. However, the lack of large, pure crystals has prevented the characterization of intrinsic properties and has delayed deposition-based metastable growth efforts. Here, we report an optimized synthesis methodology for single-crystalline Na4Si24 with crystals approaching the millimeter-size scale with conditions near 9 GPa and 1123 K. Single-crystal diffraction was used to confirm the open-framework structure, and Na atoms remain highly mobile within the framework channels, as determined by electrical conductivity and electron energy loss spectroscopy (EELS) measurements. An epitaxial relationship between Na4Si24 and diamond cubic silicon (DC-Si), observed through high-resolution transmission electron microscopy (HRTEM), is proposed to facilitate the growth of high-quality Na4Si24 crystals from DC-Si wafers mixed with metallic Na, and could provide a viable path forward for scaling efforts of Na4Si24 and Si24.
An entry from the Inorganic Crystal Structure Database, the world's repository for inorganic ... more An entry from the Inorganic Crystal Structure Database, the world's repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bulletin of the American Physical Society, 2018
Journal of Physics: Conference Series, 2017
On the Spin-orbit Coupling in the Ground States of AsH and AsD B Lindgren New books on physics an... more On the Spin-orbit Coupling in the Ground States of AsH and AsD B Lindgren New books on physics and related sciences Elena V Zakharova A simple deposition method for self-assembling single crystalline hybrid perovskite nanostructures Wen-Rong Xie, Bin Liu, Tao Tao et al. On the stability of the rectilinear motions in the sextupole rf trap C. M. Niculae How the type of input function affects the dynamic response of conducting polymer actuators Xingcan Xiang, Gursel Alici, Rahim Mutlu et al.
Phosphorus, Sulfur, and Silicon and the Related Elements, 2017
Abstract A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistr... more Abstract A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistry route from evaporation of aqueous solution. It crystallizes in the space group Pī with Z = 2 and the following unit cell dimensions: a = 6.4609(2), b = 6.9810(2), c = 9.813(4) Ǻ, α = 81.345(3), β = 80.547(3), γ = 88.430(3)°. IR spectroscopy confirmed the presence of P-OH group, and both ammonia and water molecule in the studied material. The thermal decomposition of [HGdP2O7 · 2 H2O] · NH3, as investigated by Controlled Rate Thermal Analysis, took place in three stages between -23 and 600 °C leading to the anhydrous salt HGdP2O7. The calcination of the synthesized product at 850 °C in a static air furnace allowed us to obtain the tetraphosphate Gd2P4O13. X-ray powder diffraction and infrared spectroscopy were used to identify these materials. The electrical properties of HGdP2O7 and Gd2P4O13 were investigated through impedance complex analysis. Modest conductivity has been observed in both materials at relatively medium temperature range. Activation energies of 0.62 and 1.21 eV, were deduced from the Arrhenius plots for HGdP2O7 and Gd2P4O13, respectively. GRAPHICAL ABSTRACT
Inorganic Chemistry, 2016
Phase-pure samples of a metastable allotrope of silicon, Si−III or BC8, were synthesized by direc... more Phase-pure samples of a metastable allotrope of silicon, Si−III or BC8, were synthesized by direct elemental transformation at 14 GPa and ∼900 K and also at significantly reduced pressure in the Na−Si system at 9.5 GPa by quenching from high temperatures ∼1000 K. Pure sintered polycrystalline ingots with dimensions ranging from 0.5 to 2 mm can be easily recovered at ambient conditions. The chemical route also allowed us to decrease the synthetic pressures to as low as 7 GPa, while pressures required for direct phase transition in elemental silicon are significantly higher. In situ control of the synthetic protocol, using synchrotron radiation, allowed us to observe the underlying mechanism of chemical interactions and phase transformations in the Na−Si system. Detailed characterization of Si−III using X-ray diffraction, Raman spectroscopy, 29 Si NMR spectroscopy, and transmission electron microscopy are discussed. These large-volume syntheses at significantly reduced pressures extend the range of possible future bulk characterization methods and applications.
Data Revues 16310748 00090011 06000932, Feb 14, 2008
Journal of Superhard Materials, 2009
Phase relations and chemical interaction in the B-BN system have been studied in situ using X ray... more Phase relations and chemical interaction in the B-BN system have been studied in situ using X ray diffraction with synchrotron radiation at pressures to 5.3 GPa and temperatures to 2700 K. The results obtained have been used for the thermodynamic analysis of this system and for the construction of its phase diagram at 5 GPa. The values of thermodynamic functions of the phases competing in the B-BN system at high pressures and temperatures have been calculated in the framework of phenomenological models, unknown parameters of which have been found from the experimental data. It has been shown that only one thermodynamically stable boron subnitride (rhombohedral B 13 N 2) exists in the system. It melts incongruently and forms an eutectic equilibrium with boron.
Solid State Communications, 2005
Quasi-hydrostatic compression of aluminum carbide, Al 4 C 3 has been studied to 6 GPa at room tem... more Quasi-hydrostatic compression of aluminum carbide, Al 4 C 3 has been studied to 6 GPa at room temperature using energydispersive X-ray powder diffraction with synchrotron radiation. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 130(5) GPa and the first pressure derivative of the bulk modulus, B 0 0 , of 4.6(9). The compression is found to be anisotropic, with the a-axis being more compressible than the c-axis.
Journal of Superhard Materials, 2012
ChemInform, 2014
Synthesis of -Mg 2C3: A Monoclinic High-Pressure Polymorph of Magnesium Sesquicarbide.-The new t... more Synthesis of -Mg 2C3: A Monoclinic High-Pressure Polymorph of Magnesium Sesquicarbide.-The new title polymorph of Mg 2C3 is prepared from the elements under high pressure/high temperature conditions (9-20 GPa, 1700-2000 K) and characterized by synchrotron powder XRD, mass spectrometry, solid state NMR and Raman spectroscopy, and DFT calculations. The new polymorph crystallizes in the monoclinic space group C2/m and contains linear chains, which are nearly aligned along the crystallographic c-axis. At pressures below 19 GPa, -Mg 2C3 is thermodynamically metastable and becomes a stable structure above 19 GPa.-(STROBEL*,
The Journal of Physical Chemistry C, 2014
The high-pressure and high-temperature formation and stability of recently discovered magnesium c... more The high-pressure and high-temperature formation and stability of recently discovered magnesium carbide Mg 2 C were studied by in situ X-ray diffraction up to 20 GPa and 1550 K. The insights into the thermodynamics of Mg 2 C under extreme conditions, and its metastability at 0.1 MPa and 300 K, were provided by ab initio calculations of total energies and phonon density of states as a function of pressure. We illustrate how the compound found occasionally in high-pressure experiments could be systematically predicted and discovered in a time-saving way. Similar theoretical approaches can be useful for prediction of synthesis conditions and recovery of new solids.
The Journal of Physical Chemistry B, 2008
X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interact... more X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interaction of-rhombohedral boron with boron (III) oxide and phase relations in the B-B 2 O 3 system at pressures up to 6 GPa in the temperature range from 300 to 2800 K. The B-B 2 O 3 system has been thermodynamically analyzed, and its equilibrium phase diagram at 5 GPa has been constructed. Only one thermodynamically stable boron suboxide, B 6 O, exists in the system. It forms eutectic equilibria with boron and B 2 O 3 .
Solid State Communications, 2005
Quasi-hydrostatic compression of aluminum silicon carbide, a-Al 4 SiC 4 , has been studied up to ... more Quasi-hydrostatic compression of aluminum silicon carbide, a-Al 4 SiC 4 , has been studied up to 6 GPa at room temperature using energy-dispersive X-ray powder diffraction with synchrotron radiation. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 182(10) GPa with fixed first pressure derivative of the bulk modulus, B 0 0 , of 4.0. The compression is found to be anisotropic with higher compressibility along c-axis.
Solid State Communications, 2009
Quasi-hydrostatic compression of rhombohedral boron subnitride has been studied up to 30 GPa at r... more Quasi-hydrostatic compression of rhombohedral boron subnitride has been studied up to 30 GPa at room temperature using angle-dispersive X-ray diffraction with synchrotron radiation. The α-rhombohedral boron type R3m structure of B 13 N 2 is stable in the whole pressure range under study. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 200(15) GPa with fixed first pressure derivative of the bulk modulus, B 0 , of 4.0. The compression is found to be slightly anisotropic with higher compressibility along c-axis.
Physical Review B, 2009
The response of graphitelike boron-carbon phases to shock wave loading has been investigated usin... more The response of graphitelike boron-carbon phases to shock wave loading has been investigated using short laser-driven pressure pulses. The main motivation, related to wide technological applications, was to study the possibility to synthesize via dynamic compression the B-doped diamond produced recently under high static pressures and temperatures. Over the explored range of shock pressure, no formation of such diamondlike phase has been observed. Instead, Raman and x-ray diffraction studies of the recovered samples have shown presence of mixtures of disordered graphite and boron carbide. Quantitative analysis of shock and release wave propagation in the multilayered targets has been performed, combining time-resolved measurements and simulations. It was found that despite the high amplitudes of the laser shocks, up to about 70 GPa, the pressure and temperature transmitted into the B-C specimens probably outlaid the p-T conditions required for the phase transition into diamondlike structures.
Journal of Physics: Condensed Matter, 2007
New nanomaterials have been prepared by high-temperature treatment of fullerite C60 at moderate (... more New nanomaterials have been prepared by high-temperature treatment of fullerite C60 at moderate (0.1-1.5 GPa) pressures attainable for large-volume pressure apparatus. The structure, EELS spectra, Raman spectra, hardness and elastic moduli of these carbon substances have been studied. The materials have a high (90%) elastic recovery, fairly high hardness H~10-15 GPa and record values of the hardness-to-Young-modulus ratio H/E~0.22. The
Physical Review Letters, Jan 9, 2009
Here, we report the synthesis of cubic BC 5 (c-BC 5), the diamondlike B-C phase with the highest ... more Here, we report the synthesis of cubic BC 5 (c-BC 5), the diamondlike B-C phase with the highest boron content ever achieved, at 24 GPa and about 2200 K, using both a laser-heated diamond anvil cell and large-volume multianvil apparatus. The synthesized phase is low compressible (bulk modulus of 335 GPa), conductive, and exhibits extreme Vickers hardness (71 GPa), unusually high for superhard materials fracture toughness (9:5 MPa m 0:5), and high thermal stability (up to 1900 K); this makes it an exceptional superabrasive and promising material for high-temperature electronics.
Crystal Growth & Design, Oct 8, 2018
Na4Si24 is the precursor to Si24, a recently discovered allotrope of silicon. With a quasidirect ... more Na4Si24 is the precursor to Si24, a recently discovered allotrope of silicon. With a quasidirect band gap near 1.3 eV, Si24 has potential to transform silicon-based optoelectronics including solar energy conversion. However, the lack of large, pure crystals has prevented the characterization of intrinsic properties and has delayed deposition-based metastable growth efforts. Here, we report an optimized synthesis methodology for single-crystalline Na4Si24 with crystals approaching the millimeter-size scale with conditions near 9 GPa and 1123 K. Single-crystal diffraction was used to confirm the open-framework structure, and Na atoms remain highly mobile within the framework channels, as determined by electrical conductivity and electron energy loss spectroscopy (EELS) measurements. An epitaxial relationship between Na4Si24 and diamond cubic silicon (DC-Si), observed through high-resolution transmission electron microscopy (HRTEM), is proposed to facilitate the growth of high-quality Na4Si24 crystals from DC-Si wafers mixed with metallic Na, and could provide a viable path forward for scaling efforts of Na4Si24 and Si24.
An entry from the Inorganic Crystal Structure Database, the world's repository for inorganic ... more An entry from the Inorganic Crystal Structure Database, the world's repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Bulletin of the American Physical Society, 2018
Journal of Physics: Conference Series, 2017
On the Spin-orbit Coupling in the Ground States of AsH and AsD B Lindgren New books on physics an... more On the Spin-orbit Coupling in the Ground States of AsH and AsD B Lindgren New books on physics and related sciences Elena V Zakharova A simple deposition method for self-assembling single crystalline hybrid perovskite nanostructures Wen-Rong Xie, Bin Liu, Tao Tao et al. On the stability of the rectilinear motions in the sextupole rf trap C. M. Niculae How the type of input function affects the dynamic response of conducting polymer actuators Xingcan Xiang, Gursel Alici, Rahim Mutlu et al.
Phosphorus, Sulfur, and Silicon and the Related Elements, 2017
Abstract A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistr... more Abstract A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistry route from evaporation of aqueous solution. It crystallizes in the space group Pī with Z = 2 and the following unit cell dimensions: a = 6.4609(2), b = 6.9810(2), c = 9.813(4) Ǻ, α = 81.345(3), β = 80.547(3), γ = 88.430(3)°. IR spectroscopy confirmed the presence of P-OH group, and both ammonia and water molecule in the studied material. The thermal decomposition of [HGdP2O7 · 2 H2O] · NH3, as investigated by Controlled Rate Thermal Analysis, took place in three stages between -23 and 600 °C leading to the anhydrous salt HGdP2O7. The calcination of the synthesized product at 850 °C in a static air furnace allowed us to obtain the tetraphosphate Gd2P4O13. X-ray powder diffraction and infrared spectroscopy were used to identify these materials. The electrical properties of HGdP2O7 and Gd2P4O13 were investigated through impedance complex analysis. Modest conductivity has been observed in both materials at relatively medium temperature range. Activation energies of 0.62 and 1.21 eV, were deduced from the Arrhenius plots for HGdP2O7 and Gd2P4O13, respectively. GRAPHICAL ABSTRACT
Inorganic Chemistry, 2016
Phase-pure samples of a metastable allotrope of silicon, Si−III or BC8, were synthesized by direc... more Phase-pure samples of a metastable allotrope of silicon, Si−III or BC8, were synthesized by direct elemental transformation at 14 GPa and ∼900 K and also at significantly reduced pressure in the Na−Si system at 9.5 GPa by quenching from high temperatures ∼1000 K. Pure sintered polycrystalline ingots with dimensions ranging from 0.5 to 2 mm can be easily recovered at ambient conditions. The chemical route also allowed us to decrease the synthetic pressures to as low as 7 GPa, while pressures required for direct phase transition in elemental silicon are significantly higher. In situ control of the synthetic protocol, using synchrotron radiation, allowed us to observe the underlying mechanism of chemical interactions and phase transformations in the Na−Si system. Detailed characterization of Si−III using X-ray diffraction, Raman spectroscopy, 29 Si NMR spectroscopy, and transmission electron microscopy are discussed. These large-volume syntheses at significantly reduced pressures extend the range of possible future bulk characterization methods and applications.
Data Revues 16310748 00090011 06000932, Feb 14, 2008
Journal of Superhard Materials, 2009
Phase relations and chemical interaction in the B-BN system have been studied in situ using X ray... more Phase relations and chemical interaction in the B-BN system have been studied in situ using X ray diffraction with synchrotron radiation at pressures to 5.3 GPa and temperatures to 2700 K. The results obtained have been used for the thermodynamic analysis of this system and for the construction of its phase diagram at 5 GPa. The values of thermodynamic functions of the phases competing in the B-BN system at high pressures and temperatures have been calculated in the framework of phenomenological models, unknown parameters of which have been found from the experimental data. It has been shown that only one thermodynamically stable boron subnitride (rhombohedral B 13 N 2) exists in the system. It melts incongruently and forms an eutectic equilibrium with boron.
Solid State Communications, 2005
Quasi-hydrostatic compression of aluminum carbide, Al 4 C 3 has been studied to 6 GPa at room tem... more Quasi-hydrostatic compression of aluminum carbide, Al 4 C 3 has been studied to 6 GPa at room temperature using energydispersive X-ray powder diffraction with synchrotron radiation. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 130(5) GPa and the first pressure derivative of the bulk modulus, B 0 0 , of 4.6(9). The compression is found to be anisotropic, with the a-axis being more compressible than the c-axis.
Journal of Superhard Materials, 2012
ChemInform, 2014
Synthesis of -Mg 2C3: A Monoclinic High-Pressure Polymorph of Magnesium Sesquicarbide.-The new t... more Synthesis of -Mg 2C3: A Monoclinic High-Pressure Polymorph of Magnesium Sesquicarbide.-The new title polymorph of Mg 2C3 is prepared from the elements under high pressure/high temperature conditions (9-20 GPa, 1700-2000 K) and characterized by synchrotron powder XRD, mass spectrometry, solid state NMR and Raman spectroscopy, and DFT calculations. The new polymorph crystallizes in the monoclinic space group C2/m and contains linear chains, which are nearly aligned along the crystallographic c-axis. At pressures below 19 GPa, -Mg 2C3 is thermodynamically metastable and becomes a stable structure above 19 GPa.-(STROBEL*,
The Journal of Physical Chemistry C, 2014
The high-pressure and high-temperature formation and stability of recently discovered magnesium c... more The high-pressure and high-temperature formation and stability of recently discovered magnesium carbide Mg 2 C were studied by in situ X-ray diffraction up to 20 GPa and 1550 K. The insights into the thermodynamics of Mg 2 C under extreme conditions, and its metastability at 0.1 MPa and 300 K, were provided by ab initio calculations of total energies and phonon density of states as a function of pressure. We illustrate how the compound found occasionally in high-pressure experiments could be systematically predicted and discovered in a time-saving way. Similar theoretical approaches can be useful for prediction of synthesis conditions and recovery of new solids.
The Journal of Physical Chemistry B, 2008
X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interact... more X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interaction of-rhombohedral boron with boron (III) oxide and phase relations in the B-B 2 O 3 system at pressures up to 6 GPa in the temperature range from 300 to 2800 K. The B-B 2 O 3 system has been thermodynamically analyzed, and its equilibrium phase diagram at 5 GPa has been constructed. Only one thermodynamically stable boron suboxide, B 6 O, exists in the system. It forms eutectic equilibria with boron and B 2 O 3 .
Solid State Communications, 2005
Quasi-hydrostatic compression of aluminum silicon carbide, a-Al 4 SiC 4 , has been studied up to ... more Quasi-hydrostatic compression of aluminum silicon carbide, a-Al 4 SiC 4 , has been studied up to 6 GPa at room temperature using energy-dispersive X-ray powder diffraction with synchrotron radiation. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 182(10) GPa with fixed first pressure derivative of the bulk modulus, B 0 0 , of 4.0. The compression is found to be anisotropic with higher compressibility along c-axis.
Solid State Communications, 2009
Quasi-hydrostatic compression of rhombohedral boron subnitride has been studied up to 30 GPa at r... more Quasi-hydrostatic compression of rhombohedral boron subnitride has been studied up to 30 GPa at room temperature using angle-dispersive X-ray diffraction with synchrotron radiation. The α-rhombohedral boron type R3m structure of B 13 N 2 is stable in the whole pressure range under study. A fit of the experimental p-V data to the Birch equation of state yields the values of the bulk modulus, B 0 , of 200(15) GPa with fixed first pressure derivative of the bulk modulus, B 0 , of 4.0. The compression is found to be slightly anisotropic with higher compressibility along c-axis.
Physical Review B, 2009
The response of graphitelike boron-carbon phases to shock wave loading has been investigated usin... more The response of graphitelike boron-carbon phases to shock wave loading has been investigated using short laser-driven pressure pulses. The main motivation, related to wide technological applications, was to study the possibility to synthesize via dynamic compression the B-doped diamond produced recently under high static pressures and temperatures. Over the explored range of shock pressure, no formation of such diamondlike phase has been observed. Instead, Raman and x-ray diffraction studies of the recovered samples have shown presence of mixtures of disordered graphite and boron carbide. Quantitative analysis of shock and release wave propagation in the multilayered targets has been performed, combining time-resolved measurements and simulations. It was found that despite the high amplitudes of the laser shocks, up to about 70 GPa, the pressure and temperature transmitted into the B-C specimens probably outlaid the p-T conditions required for the phase transition into diamondlike structures.
Journal of Physics: Condensed Matter, 2007
New nanomaterials have been prepared by high-temperature treatment of fullerite C60 at moderate (... more New nanomaterials have been prepared by high-temperature treatment of fullerite C60 at moderate (0.1-1.5 GPa) pressures attainable for large-volume pressure apparatus. The structure, EELS spectra, Raman spectra, hardness and elastic moduli of these carbon substances have been studied. The materials have a high (90%) elastic recovery, fairly high hardness H~10-15 GPa and record values of the hardness-to-Young-modulus ratio H/E~0.22. The