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Related papers: Computational searches for iron oxides at high pre…

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A statistical numerical analysis of thermogravimetric measurements (temperature, mass variation, oxygen pressure) leads to a new equilibrium phase diagram T-P-X of the iron monoxide or w\"ustite FeOx. Three varieties or pseudo phases W1,…

Materials Science · Physics 2021-11-09 Pierre Vallet , Claude Carel

Germanates are often used as structural analogs of planetary silicates. We have explored the high-pressure phase relations in Mg$_2$GeO$_4$ using diamond anvil cell experiments combined with synchrotron x-ray diffraction and computations…

Geophysics · Physics 2024-03-06 R. V. Divya , G. Kumar , R. E. Cohen , S. J. Tracy , Y. Meng , S. Chariton , V. B. Prakapenka , R. Dutta

Water and hydrogen at high pressure make up a substantial fraction of the interiors of giant planets. Using ab initio random structure search methods we investigate the ground-state crystal structures of water, hydrogen, and hydrogen-oxygen…

Materials Science · Physics 2013-02-01 Shuai Zhang , Hugh Wilson , Kevin Driver , Burkhard Militzer

Nitrogen oxides are textbook class of molecular compounds, with extensive industrial applications. Nitrogen and oxygen are also among the most abundant elements in the universe. We explore the N-O system at 0 K and up to 500 GPa though ab…

Materials Science · Physics 2015-06-30 Dongxu Li , Artem R. Oganov , Xiao Dong , Xiang-Feng Zhou , Qiang Zhu , Guangrui Qian , Huafeng Dong

Experimentally discovered compounds in the iron-nitrogen system belong to the low concentration part of the Fe-N phase diagram. In our paper, which is based on ab initio calculations we have studied formation and stability of high-pressure…

Materials Science · Physics 2019-03-27 Alexey Kartsev , Oleg Feya , Nina Bondarenko , Alexander G. Kvashnin , Artem Oganov

We have studied solid hydrogen up to pressures of 300 GPa and temperatures of 350 K using density functional theory methods and have found "mixed structures" that are more stable than those predicted earlier. Mixed structures consist of…

Materials Science · Physics 2012-06-20 Chris J. Pickard , Miguel Martinez-Canales , Richard J. Needs

In order to study the performance of interatomic potentials and their reliability at higher pressures, the phase diagram of four different embedded-atom type potential models of iron is compared. The calculations were done by the nested…

Materials Science · Physics 2018-03-23 Livia B. Partay

The emission spectra and the ionization structure of the low ionization stages of iron, Fe I--IV, in gaseous nebulae are studied. This work includes: (i) new atomic data: photoionization cross sections, total e-ion recombination rates,…

Astrophysics · Physics 2009-10-30 Manuel A. Bautista , Anil K. Pradhan

Properties of iron oxides at the extreme conditions are of essential importance in condensed matter physics and Geophysics. The recent discovery of a new type of iron oxide, Fe4O5, at high pressure and high temperature of Earth's deep…

Strongly Correlated Electrons · Physics 2021-09-14 Aiqin Yang , Qiaoying Qin , Xiangru Tao , Shengli Zhang , Yongtao Zhao , Peng Zhang

\textit{Ab initio} random structure searching based on density functional theory is used to determine the ground-state structures of ice at high pressures. Including estimates of lattice zero-point energies, ice is found to adopt three…

Other Condensed Matter · Physics 2013-05-29 Jeffrey M. McMahon

Structural, magnetic and electrical-transport properties of {\alpha}-LiFeO2, crystallizing in the rock salt structure with random distribution of Li and Fe ions, have been studied by synchrotron X-ray diffraction, 57Fe M\"ossbauer…

Strongly Correlated Electrons · Physics 2017-09-29 Samar Layek , Eran Greenberg , Weiming Xu , Gregory Kh. Rozenberg , Moshe P. Pasternak , Jean-Paul Itié , Dániel G. Merkel

We used ab initio random structure searching (AIRSS) to investigate polymorphism in C3N4 carbon nitride as a function of pressure. Our calculations reveal new framework structures, including a particularly stable chiral polymorph of space…

Materials Science · Physics 2016-09-14 Chris J. Pickard , Ashkan Salamat , Michael J. Bojdys , Richard J. Needs , Paul F. McMillan

In this work we perform a systematic calculation of the Fe-Ta phase diagram to discover novel hard magnetic phases. By using structure prediction methods based on evolutionary algorithms, we identify two new energetically stable magnetic…

Materials Science · Physics 2020-01-29 Sergiu Arapan , Pablo Nieves , Heike C. Herper , Dominik Legut

A subtle balance between competing interactions in strongly correlated systems can be easily tipped by additional interfacial interactions in a heterostructure. This often induces exotic phases with unprecedented properties, as recently…

The crystal structure of solid oxygen at low temperatures and at pressures up to 7 GPa is studied by theoretical calculations. In the calculations, the adiabatic potential of the crystal is approximated by a superposition of pair-potentials…

Materials Science · Physics 2009-11-13 Kazuki Nozawa , Nobuyuki Shima , Kenji Makoshi

We propose three new phases of H2O under ultrahigh pressure. Our structural search was performed using an adaptive genetic algorithm which allows an extensive exploration of crystal structure. The new sequence of pressure-induced…

Materials Science · Physics 2013-05-29 Min Ji , Koichiro Umemoto , Cai-Zhuang Wang , Kai-Ming Ho , Renata M. Wentzcovitch

The crystal structure of the iron oxide gamma-Fe2O3 is usually reported in either the cubic system (space group P4332) with partial Fe vacancy disorder or in the tetragonal system (space group P41212) with full site ordering and c/a\approx…

Materials Science · Physics 2015-05-19 Ricardo Grau-Crespo , Asmaa Y. Al-Baitai , Iman Saadoune , Nora H. De Leeuw

Static magnetic order of quasi two-dimensional FeAs compounds Sr4A2O6-xFe2As2, with A = Sc and V, has been detected by 57Fe Moessbauer and muon spin relaxation ({\mu}SR) spectroscopies. The non-superconducting stoichiometric (x = 0) A = Sc…

Group I/II materials exhibit unexpected structural phase transitions at high pressures, providing potential insight into the origins of elemental superconductivity. We present here a computational study of elemental barium and binary…

Materials Science · Physics 2012-07-16 Joshua A. Taillon , William W. Tipton , Richard G. Hennig

In this paper, we revisit the high-pressure behavior of BaZrO3 by a combination of first-principle calculations, Raman spectroscopy, and x-ray diffraction under high pressure. We confirm experimentally the cubic-to-tetragonal transition at…