Structural and magnetic properties of chromium dioxide at high pressures |
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Authors: | Yinwei Li Jian Hao |
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Affiliation: | 1. College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, PR China;2. College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, PR China;1. Instituto de Física, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro 21941-972, Brazil;2. Racah Institute of Physics, The Hebrew University, 91904 Jerusalem, Israel;1. Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan;2. Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki, 319-1195, Japan;3. Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Ibaraki, 319-1106, Japan;4. Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan;1. Research Laboratory of Functional Materials Technologies, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena 3/7, 1048, Riga, Latvia;2. Institute of Physics, University of Tartu, Wilhelm Ostwald Str. 1, 50411, Tartu, Estonia;3. Institute of Physics, University of Latvia, Miera 32, 2169, Salaspils, Latvia;4. Institute of Materials, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland;5. Helmholz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, 14109, Germany |
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Abstract: | Ab initio calculations were performed on CrO2 to study its behavior and possible similarity to silica under high pressures. At the rutile→CaCl2-type phase transition, the lattice constants, cell volume and total energy change continuously, indicating the second-order nature of the phase transition, consistent with the experimental observations. The current calculations have demonstrated that the rutile→CaCl2-type phase transition is driven by the softening of the Raman active B1g mode, weakly coupling with the elastic shear modulus Cs. Further phase transitions of CrO2 to denser packed phases of α-PbO2-type and pyrite have been well predicted by total energy calculations. Our electronic calculations revealed that CrO2 is still a half-metallic ferromagnet up to pressure of 95 GPa. The present results confirm the analogy of the phase sequence between silica and CrO2 at high pressures. |
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