TY - JOUR
T1 - Ultrahigh-Pressure Behavior of AO2 (A = Sn, Pb, Hf) Compounds
AU - Dutta, Rajkrishna
AU - Kiefer, Boris
AU - Greenberg, Eran
AU - Prakapenka, Vitali B.
AU - Duffy, Thomas S.
N1 - Funding Information:
The authors are grateful to S. J. Tracy and S. Tkachev for assistance. This study was funded by the National Science Foundation (NSF, EAR-1415321, and EAR-1836852). Use of the Advanced Photon Source, operated for the U.S. Department of Energy, Office of Science by Argonne National Laboratory, under Contract DE-AC02-06CH11357 is acknowledged. GeoSoilEnviroCARS (GSECARS, Sector 13) is supported by the NSF Earth Sciences (Grant EAR-1634415), and the Department of Energy, Geosciences (Grant DE-FG02-94ER14466), is acknowledged. B.K. acknowledges computing resources provided through the NSF (XSEDE) under Grant DMR TG-110093. The gas-loading facility at GSECARS is partially supported by the Consortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement EAR 1606856.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019
Y1 - 2019
N2 - The high-pressure behavior of metal dioxides, AO2, is of wide interest due to their extensive polymorphism. In this study, high-pressure phase transitions in dioxides of selected group 4 and 14 elements (SnO2, PbO2, and HfO2) were examined by using in situ X-ray diffraction in the laser-heated diamond anvil cell to âˆ200 GPa and theoretical density functional theory calculations to 600 GPa. The cotunnite-type phase was found to be stable up to the maximum pressure in SnO2 and PbO2. For HfO2, a transition from the cotunnite to the Fe2P-type phase was observed in experiments at pressures >125 GPa, in agreement with our theoretical computations that predict a transition pressure of 111-137 GPa. Our calculations also predict a re-entrant cotunnite phase in HfO2 above 305-314 GPa that subsequently transforms into the Ni2In-type phase at 390-469 GPa. The transition sequences predicted in these oxides are consistent among three different exchange-correlation functionals and can be explained by the energetic competition of stationary electronic flat bands and a pressure-induced shift of electronic states to lower energies. ©
AB - The high-pressure behavior of metal dioxides, AO2, is of wide interest due to their extensive polymorphism. In this study, high-pressure phase transitions in dioxides of selected group 4 and 14 elements (SnO2, PbO2, and HfO2) were examined by using in situ X-ray diffraction in the laser-heated diamond anvil cell to âˆ200 GPa and theoretical density functional theory calculations to 600 GPa. The cotunnite-type phase was found to be stable up to the maximum pressure in SnO2 and PbO2. For HfO2, a transition from the cotunnite to the Fe2P-type phase was observed in experiments at pressures >125 GPa, in agreement with our theoretical computations that predict a transition pressure of 111-137 GPa. Our calculations also predict a re-entrant cotunnite phase in HfO2 above 305-314 GPa that subsequently transforms into the Ni2In-type phase at 390-469 GPa. The transition sequences predicted in these oxides are consistent among three different exchange-correlation functionals and can be explained by the energetic competition of stationary electronic flat bands and a pressure-induced shift of electronic states to lower energies. ©
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U2 - 10.1021/acs.jpcc.9b06856
DO - 10.1021/acs.jpcc.9b06856
M3 - Article
AN - SCOPUS:85074757076
SN - 1932-7447
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
ER -