Article
Geochemistry & Geophysics
Chaoshuai Zhao, Chaojia Lv, Liangxu Xu, Lin Liang, Jin Liu
Summary: This study investigated the Raman modes of natural magnesite under high pressure and found changes in lattice structure, indicating the significant impact of hydrostatic conditions on the structural evolution of MgCO3. The findings provide important insights for modeling the carbon cycle in the Earth's lower mantle.
AMERICAN MINERALOGIST
(2021)
Article
Chemistry, Physical
Xiao Zhang, Yu Wang, Maxim Bykov, Elena Bykova, Stella Chariton, Vitali B. Prakapenka, Konstantin Glazyrin, Alexander F. Goncharov
Summary: Nitrogen and water react differently at extreme pressure-temperature conditions, forming clathrate compounds below 6 GPa and transforming into a fine grained state above 6 GPa. There is no sign of formation of mixed compounds and no ice doping by nitrogen observed in this study. Size effects in fine grained crystallites result in peculiar Raman spectra in the molecular regime.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Materials Science, Ceramics
Xinyu Zhang, Lidong Dai, Haiying Hu, Meiling Hong, Chuang Li
Summary: The pressure-dependent vibrational and electrical transport properties of GeTe were investigated under hydrostatic and non-hydrostatic environments using in-situ Raman spectroscopy and electrical conductivity measurements. Two structural transformations from rhombohedral to cubic NaCl-type to orthorhombic GeTe were observed at 3.2 GPa and 12.3 GPa under non-hydrostatic condition. Similarly, two corresponding phase transitions were detected at much higher pressures of 5.0 GPa and 15.4 GPa under hydrostatic condition. Additionally, an electronic transition accompanying the rhombohedral-cubic NaCl-type transition was characterized at 3.3 GPa using variable-temperature electrical conductivity experiments. The reversible nature of the structural and electronic transitions of GeTe was confirmed through recoverable Raman spectra and electrical conductivity upon decompression, as well as microscopic structural observations.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Crystallography
Meiling Hong, Lidong Dai, Haiying Hu, Xinyu Zhang
Summary: Investigations on Ga2Se3 under different hydrostatic environments up to 40.2 GPa revealed a phase transformation and semiconductor-to-metal transition at high pressures. The reversible nature of the phase transformation and metallization, along with a large pressure hysteresis effect, highlights the importance of systematic research on the high-pressure structural and electrical transport properties of Ga2Se3 for further exploration in A(2)B(3)-type compounds.
Article
Chemistry, Physical
Demetrio Scelta, Matteo Ceppatelli, Roberto Bini, Anna Pakhomova, Gaston Garbarino, Mohamed Mezouar, Mario Santoro
Summary: Experimental investigations were conducted on the high temperature transformation of amorphous polymeric carbon monoxide (pCO) in the pressure range of 47-120 GPa. The results showed that the decomposition of a-pCO into CO2 and likely a mixture of amorphous CxOy suboxides and amorphous carbon occurred, supporting the theoretical understanding. It was also found that the decomposition was strongly pressure-dependent with a steep pressure-temperature kinetic barrier.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Geochemistry & Geophysics
Xinyu Zhang, Lidong Dai, Haiying Hu, Chuang Li
Summary: In situ Raman scattering and electrical conductivity experiments were conducted to investigate the structural phase transitions of calcite under high pressures. The results showed that calcite underwent multiple phase transitions during compression and decompression, which were evidenced by the changes in Raman peaks and electrical conductivity. The phase transitions were found to be reversible, except for the CaCO3-VI to CaCO3-III transition which exhibited a pressure hysteresis. The temperature-pressure relation of the CaCO3-III to CaCO3-VI transition was also determined. The obtained phase diagram provides insights into the high-pressure behavior of carbonate minerals.
Article
Physics, Applied
Xinyu Zhang, Lidong Dai, Haiying Hu, Meiling Hong
Summary: Experiments observed a phase transition of gallium arsenide from zinc-blende to orthorhombic structure at 12.2 GPa under high pressure, with the high-pressure phase exhibiting metallic behavior. The reversibility of the phase transition upon decompression was confirmed, further verified by HRTEM and AFM images.
MODERN PHYSICS LETTERS B
(2021)
Article
Geochemistry & Geophysics
M. J. Rucks, J. M. Winey, Y. Toyoda, Y. M. Gupta, T. S. Duffy
Summary: Natural fluorapatite from Durango, Mexico exhibits elastic and inelastic responses under shock wave loading between 14.5 and 119.5 GPa. At shock pressures above 80 GPa, fluorapatite undergoes a transition to a denser structure, exceeding the predicted density. The shock response of fluorapatite is similar to enstatite but stiffer than quartz and albite at the examined stresses.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Materials Science, Multidisciplinary
Maxim Bykov, Elena Bykova, Chris J. Pickard, Miguel Martinez-Canales, Konstantin Glazyrin, Jesse S. Smith, Alexander F. Goncharov
Summary: The study identified the structure of the high-pressure phase of molecular methane using single-crystal synchrotron x-ray diffraction, Raman spectroscopy, and first principles calculations. It revealed the relationship between the high-pressure phase and the previously documented phase B, and determined the positions of hydrogen atoms through calculations. The study's findings differ from previous proposals of multiple high-pressure phases based solely on Raman spectroscopy results.
Article
Physics, Condensed Matter
O. I. Barkalov, M. A. Kuzovnikov, I. A. Sholin, N. S. Orlov
Summary: The phase transformations of silicon clathrate Si-136 under high hydrogen pressure were studied, revealing pressure-dependent vibrational mode frequencies that agreed with ab initio calculations. At 10 GPa, Si-136 transformed into a mixture of Si-II and Si-III phases, with no observed interaction between hydrogen and silicon during compression or decompression.
SOLID STATE COMMUNICATIONS
(2021)
Article
Instruments & Instrumentation
S. I. Ninenko, V. V. Brazhkin
Summary: An experimental setup with a large working volume has been developed to investigate the optical properties of gases, liquids, and solutions at a wide range of temperatures and high hydrostatic pressures. The setup allows for accurate control of experimental parameters and can be operated for several hours. The main focus of the experiments is to study the Raman radiation in supercritical fluids of molecular substances.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Chemistry, Multidisciplinary
Wei Zhang, Lei Liu, Zhao-Xia Ma, Yang Liu, Zhi-Guo Li, Hua-Zhong Guo
Summary: This study conducted a series of plate-impact experiments to investigate the dynamic response of 2050-T84 Al-Li alloy under shock compression. The Hugoniot elastic limit, spall strength, and Hugoniot state were determined, and the results were compared with theoretical calculations. The obtained data can guide the design of protective structures for spacecraft or artificial satellites, and lightweight aluminum alloy armor plates.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Geosciences, Multidisciplinary
Yohan Park, Shintaro Azuma, Keishi Okazaki, Kentaro Uesugi, Masahiro Yasutake, Yu Nishihara, Ryuichi Nomura
Summary: The seismic anisotropy in Earth's lowermost mantle (D '' layer) is likely caused by the lattice-preferred orientation (LPO) induced by plastic deformation in mantle materials. Ferropericlase, as the second most abundant mineral in the lower mantle, may contribute significantly to the observed seismic anisotropy in the D '' layer. Our experiments show that {100}<011> is the dominant slip system in the D '' layer.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Materials Science, Multidisciplinary
S. E. Finnegan, C. Storm, E. J. Pace, M. McMahon, S. G. MacLeod, E. Plekhanov, N. Bonini, C. Weber
Summary: Angle-dispersive x-ray powder diffraction experiments were conducted on neodymium metal up to a pressure of 302 GPa, revealing multiple phase transitions. Electronic structure calculations confirmed the observed structural sequence and predicted transition pressures. The disappearance of magnetism was found to be a key factor in phase transitions, along with enthalpy and volume changes. Additionally, comparisons with similar phases in samarium showed interesting differences in behavior under high pressure conditions.
Article
Chemistry, Physical
Josu Sanchez-Martin, Julio Pellicer-Porres, Akun Liang, Jordi Ibanez, Robert Oliva, Catalin Popescu, Zhangzhen He, Placida Rodriguez-Hernandez, Alfonso Munoz, Daniel Errandonea
Summary: The vibrational and structural behaviors of Ni3V2O8 and Co3V2O8 orthovanadates under high pressure have been studied using X-ray diffraction, Raman spectra, and theoretical simulations. Both materials exhibit stable structures throughout the entire pressure range.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Applied
Natalia V. Morozova, Igor V. Korobeinikov, Kirill V. Kurochka, Sergey V. Ovsyannikov
JOURNAL OF APPLIED PHYSICS
(2020)
Article
Physics, Applied
Natalia V. Morozova, Igor V. Korobeynikov, Sergey V. Ovsyannikov
Summary: The study showed that under high pressure, the thermoelectric power factor of SnTe can be significantly improved, with the orthorhombic phase stable over a wider pressure range. The thermopower of orthorhombic phase increases with bandgap expansion, possibly due to structural distortions.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Natalia Morozova, Igor Korobeynikov, Elena G. Shkvarina, Alexey A. Titov, Alexander N. Titov, Sergey Ovsyannikov
Summary: The study shows that the electrical conductivity type of ZrTe2 crystals can be controlled by applying different pressures, toggling between n-type, p-type, and even metallization. This control offers a potential method for diversifying the applications of conductivity in next-generation nanoelectronic devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Inorganic & Nuclear
Sergey Ovsyannikov, Alena A. Aslandukova, Andrey Aslandukov, Stella Chariton, Alexander A. Tsirlin, Igor Korobeynikov, Natalia Morozova, Timofey Fedotenko, Saiana Khandarkhaeva, Leonid Dubrovinsky
Summary: In this study, single crystals of marokite-type orthorhombic manganese oxide gamma-Mn3O4 were synthesized at high pressures. The semiconductor material exhibited two antiferromagnetic transitions and remained stable under high pressures, unlike similar iron oxides. The research highlighted significant differences in the high-pressure behavior of manganese oxides compared to iron oxides with similar stoichiometries.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Sergey Ovsyannikov, Alexander A. Tsirlin, Igor Korobeynikov, Natalia Morozova, Alena A. Aslandukova, Gerd Steinle-Neumann, Stella Chariton, Saiana Khandarkhaeva, Konstantin Glazyrin, Fabrice Wilhelm, Andrei Rogalev, Leonid Dubrovinsky
Summary: In this study, a binary ilmenite-type compound ε-Mn2O3 was synthesized under high-pressure high-temperature conditions, revealing it as an n-type semiconductor with a narrow indirect band gap and antiferromagnetic ordering. This suggests that high-pressure high-temperature conditions can induce charge disproportionation in simple transition-metal oxides, leading to the stabilization of various mixed-valence polymorphs with different structures.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Luca Bindi, Ryosuke Sinmyo, Elena Bykova, Sergey Ovsyannikov, Catherine McCammon, Ilya Kupenko, Leyla Ismailova, Leonid Dubrovinsky, Xiande Xie
Summary: A new high-pressure iron-magnesium silicate named elgoresyite has been discovered, showing potential to be a significant constituent mineral of rocky planets with relatively high MgO + FeO content. Further investigation into the phase relationships of silicates and iron oxides at higher temperature conditions is needed to test this hypothesis.
ACS EARTH AND SPACE CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Saiana Khandarkhaeva, Timofey Fedotenko, Stella Chariton, Elena Bykova, Sergey V. Ovsyannikov, Konstantin Glazyrin, Hanns-Peter Liermann, Vitali Prakapenka, Natalia Dubrovinskaia, Leonid Dubrovinsky
Summary: The study discovered two previously unknown polymorphs of magnetite at extreme high-pressure high-temperature conditions and found various iron oxide phases formed during decomposition. Crystal-chemical analysis showed a high-spin to low-spin crossover in octahedrally coordinated Fe3+ under specific pressure range, which demonstrates the possible involvement of magnetite in the deep oxygen cycle.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Natalia Morozova, Igor Korobeynikov, Nobuyoshi Miyajima, Sergey Ovsyannikov
Summary: Manipulating stress can greatly enhance the thermoelectric power factor and narrow the band gap of layered SnSe single crystals, offering a novel approach to improve the performance of thermoelectric materials.
Article
Chemistry, Multidisciplinary
Samar Layek, Eran Greenberg, Stella Chariton, Maxim Bykov, Elena Bykova, Dmytro M. Trots, Alexander Kurnosov, Irina Chuvashova, Sergey Ovsyannikov, Ivan Leonov, Gregory Kh Rozenberg
Summary: The metal-insulator transition driven by electronic correlations is a fundamental concept in condensed matter physics, and it is often accompanied by charge ordering in mixed-valence compounds. In this study, the properties of mixed-valence Fe4O5 under high pressure were investigated using experimental and computational methods, revealing a series of electronic and magnetic-state transitions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Elena Bykova, Erik Johansson, Maxim Bykov, Stella Chariton, Hongzhan Fei, Sergey V. Ovsyannikov, Alena Aslandukova, Stefan Gabel, Hendrik Holz, Benoit Merle, Bjorn Alling, Igor A. Abrikosov, Jesse S. Smith, Vitali B. Prakapenka, Tomoo Katsura, Natalia Dubrovinskaia, Alexander F. Goncharov, Leonid Dubrovinsky
Summary: A new class of rhenium borides with attractive mechanical, electronic, and other properties was identified. These compounds have a unique structural organization and potential for synthesizing new compounds with similar properties.
CHEMISTRY OF MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Patrick M. Braun, Robert J. Green, Leonid Dubrovinsky, Sergey V. Ovsyannikov, Alexander Moewes
Summary: Novel manganese phases, perovskite zeta-Mn2O3 and ilmenite epsilon-Mn2O3, were synthesized under high-pressure and high-temperature conditions. The electronic structure of these compounds was explored using X-ray absorption and X-ray emission spectroscopy techniques. The analysis of spectroscopy data allowed the determination of the concentration of different atomic sites and the characterization of crystal field and charge transfer processes near the Mn2+ crystal sites.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Natalia V. Morozova, Aleksandr Yu. Usik, Igor V. Korobeinikov, Alexander N. Titov, Sergey V. Ovsyannikov
Summary: A semiconductor-metal transition was observed in Cu-intercalated TiSe2 single crystals (x <= 0.1) at room temperature under mechanical stress. The crystals can be transformed from semiconductors to metals by applying a stress of 1-3 GPa. This suggests the potential application of CuxTiSe2 crystals in optoelectronic micro-devices where their characteristics can be controlled by stress or strain.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Inorganic & Nuclear
Sergey V. Ovsyannikov, Alexander E. Karkin, Igor V. Korobeinikov, Natalia V. Morozova, Maxim Bykov, Elena Bykova, Leonid Dubrovinsky
Summary: The researchers synthesized Fe4O5 single and polycrystals with a CaFe3O5-type structure and investigated their electronic properties. The Fe4O5 crystals demonstrated semimetal electrical conductivity under ambient conditions, with contributions from both octahedral and trigonal-prismatic iron cations. The study suggests that Fe4O5 can serve as a model for understanding other mixed-valence iron oxides and designing novel complex ones.
DALTON TRANSACTIONS
(2023)
Article
Materials Science, Multidisciplinary
Alena Aslandukova, Andrey Aslandukov, Dominique Laniel, Saiana Khandarkhaeva, Gerd Steinle-Neumann, Timofey Fedotenko, Sergey V. Ovsyannikov, Yuqing Yin, Fariia Iasmin Akbar, Konstantin Glazyrin, Michael Hanfland, Leonid Dubrovinsky, Natalia Dubrovinskaia
Summary: A high-pressure yttrium allotrope, hP3-Y, was synthesized and its stability and electronic properties were studied. Derivative hydrides, hP3-YHx, with different hydrogen contents were also synthesized. Similar structures were found for hP3-NdHx and hP3-GdHx hydrides. These results are significant for understanding the behavior and properties of materials under high pressure.
Article
Chemistry, Physical
Elena Bykova, Sergey Ovsyannikov, Maxim Bykov, Yuqing Yin, Timofey Fedotenko, Hendrik Holz, Stefan Gabel, Benoit Merle, Stella Chariton, Vitali B. Prakapenka, Natalia Dubrovinskaia, Alexander F. Goncharov, Leonid Dubrovinsky
Summary: This study reported the successful synthesis of single crystals of the stoichiometric WB4 phase under high-pressure high-temperature conditions, with a hardness reaching the level of superhard materials.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
