Metallic Aluminum Suboxides with Ultrahigh Electrical Conductivity at High Pressure
Tianheng Huang,
Cong Liu,
Junjie Wang,
Shuning Pan,
Yu Han,
Chris J. Pickard,
Ravit Helled,
Hui-Tian Wang,
Dingyu Xing,
Jian Sun
Affiliations
Tianheng Huang
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Cong Liu
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Junjie Wang
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Shuning Pan
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Yu Han
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Chris J. Pickard
Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK; Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
Ravit Helled
Institute for Computational Science, Center for Theoretical Astrophysics & Cosmology, University of Zurich, Switzerland
Hui-Tian Wang
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Dingyu Xing
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Jian Sun
National Laboratory of Solid State Microstructures, School of Physics, And Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Aluminum, as the most abundant metallic elemental content in the Earth’s crust, usually exists in the form of alumina (Al2O3). However, the oxidation state of aluminum and the crystal structures of aluminum oxides in the pressure range of planetary interiors are not well established. Here, we predicted two aluminum suboxides (Al2O, AlO) and two superoxides (Al4O7, AlO3) with uncommon stoichiometries at high pressures using first-principle calculations and crystal structure prediction methods. We find that the P4/nmm Al2O becomes stable above ~765 GPa and may survive in the deep mantles or cores of giant planets such as Neptune. Interestingly, the Al2O and AlO are metallic and have electride features, in which some electrons are localized in the interstitials between atoms. We find that Al2O has an electrical conductivity one order of magnitude higher than that of iron under the same pressure-temperature conditions, which may influence the total conductivity of giant planets. Our findings enrich the high-pressure phase diagram of aluminum oxides and improve our understanding of the interior structure of giant planets.
