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Equation of state and electronic properties of EuVO4: A high-pressure experimental and computational study

Paszkowicz, Wojciech; Lopez-Solano, Javier; Piszora, Pawel; Bojanowski, Bohdan; Mujica, Andres; Munoz, Alfonso; Cerenius, Yngve LU ; Carlson, Stefan LU and Dabkowska, Hanna (2015) In Journal of Alloys and Compounds 648. p.1005-1016
Abstract
Structural, elastic and electronic properties of zircon-type and scheelite-type EuVO4 are investigated experimentally, by in-situ X-ray diffraction using synchrotron radiation, and theoretically within the framework of the density functional theory (DFT) and using the PBE prescription of the exchange-correlation energy. This study was motivated by the fact that the previous knowledge of the equation of state (EOS) was inconclusive due to a large scatter of the experimental and theoretical data, and by the lack of information on the dependence of the electronic structure with pressure. Under the applied experimental conditions, the zircon-type structure transforms to a scheelite-type one at 7.4(2) GPa, whereas the calculations yield a lower... (More)
Structural, elastic and electronic properties of zircon-type and scheelite-type EuVO4 are investigated experimentally, by in-situ X-ray diffraction using synchrotron radiation, and theoretically within the framework of the density functional theory (DFT) and using the PBE prescription of the exchange-correlation energy. This study was motivated by the fact that the previous knowledge of the equation of state (EOS) was inconclusive due to a large scatter of the experimental and theoretical data, and by the lack of information on the dependence of the electronic structure with pressure. Under the applied experimental conditions, the zircon-type structure transforms to a scheelite-type one at 7.4(2) GPa, whereas the calculations yield a lower zircon-scheelite-coexistence pressure of 4.8 GPa. The experimental part of the study shows that the bulk modulus of the zircon-type phase is 119(3) GPa, perfectly supported by the DFT-calculated value, 119.1 GPa. The bulk modulus for the scheelite-type polymorph is higher, with an experimental value of 135(7) GPa and a theoretical one of 137.4 GPa. Compared to those reported in previous experimental and DFT or semiempirical works, the present values for the zircon-type phase are comparable or slightly lower, whereas those for the scheelite-type phase are markedly lower. Discrepancies between the present results and earlier reported ones are attributed to differences in details of the experimental method such as the pressure transmitting medium and the pressure calibration method. The calculated band structure confirms that zircon-type EuVO4 is a direct-gap semiconductor, with a bandgap energy at zero pressure of 2.88 eV. Under compression, the bandgap of the zircon phase increases with a coefficient of 10.3 meV/GPa up to the transition pressure, at which point the present calculations show a small drop of the bandgap energy. Above the transition pressure, the bandgap energy of the scheelite phase becomes almost constant, with a small pressure coefficient of just 1.5 meV/GPa. (C) 2015 Elsevier B.V. All rights reserved. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
Rare earth alloys and compounds, Elasticity, Electronic band structure, High pressure, X-ray diffraction
in
Journal of Alloys and Compounds
volume
648
pages
1005 - 1016
publisher
Elsevier
external identifiers
  • wos:000361158300143
  • scopus:84937238957
ISSN
0925-8388
DOI
10.1016/j.jallcom.2015.06.211
language
English
LU publication?
yes
id
c04a60d6-e456-4c2d-ac13-978d4e6b7957 (old id 8071094)
date added to LUP
2015-10-22 09:01:09
date last changed
2017-03-26 03:49:13
@article{c04a60d6-e456-4c2d-ac13-978d4e6b7957,
  abstract     = {Structural, elastic and electronic properties of zircon-type and scheelite-type EuVO4 are investigated experimentally, by in-situ X-ray diffraction using synchrotron radiation, and theoretically within the framework of the density functional theory (DFT) and using the PBE prescription of the exchange-correlation energy. This study was motivated by the fact that the previous knowledge of the equation of state (EOS) was inconclusive due to a large scatter of the experimental and theoretical data, and by the lack of information on the dependence of the electronic structure with pressure. Under the applied experimental conditions, the zircon-type structure transforms to a scheelite-type one at 7.4(2) GPa, whereas the calculations yield a lower zircon-scheelite-coexistence pressure of 4.8 GPa. The experimental part of the study shows that the bulk modulus of the zircon-type phase is 119(3) GPa, perfectly supported by the DFT-calculated value, 119.1 GPa. The bulk modulus for the scheelite-type polymorph is higher, with an experimental value of 135(7) GPa and a theoretical one of 137.4 GPa. Compared to those reported in previous experimental and DFT or semiempirical works, the present values for the zircon-type phase are comparable or slightly lower, whereas those for the scheelite-type phase are markedly lower. Discrepancies between the present results and earlier reported ones are attributed to differences in details of the experimental method such as the pressure transmitting medium and the pressure calibration method. The calculated band structure confirms that zircon-type EuVO4 is a direct-gap semiconductor, with a bandgap energy at zero pressure of 2.88 eV. Under compression, the bandgap of the zircon phase increases with a coefficient of 10.3 meV/GPa up to the transition pressure, at which point the present calculations show a small drop of the bandgap energy. Above the transition pressure, the bandgap energy of the scheelite phase becomes almost constant, with a small pressure coefficient of just 1.5 meV/GPa. (C) 2015 Elsevier B.V. All rights reserved.},
  author       = {Paszkowicz, Wojciech and Lopez-Solano, Javier and Piszora, Pawel and Bojanowski, Bohdan and Mujica, Andres and Munoz, Alfonso and Cerenius, Yngve and Carlson, Stefan and Dabkowska, Hanna},
  issn         = {0925-8388},
  keyword      = {Rare earth alloys and compounds,Elasticity,Electronic band structure,High pressure,X-ray diffraction},
  language     = {eng},
  pages        = {1005--1016},
  publisher    = {Elsevier},
  series       = {Journal of Alloys and Compounds},
  title        = {Equation of state and electronic properties of EuVO4: A high-pressure experimental and computational study},
  url          = {http://dx.doi.org/10.1016/j.jallcom.2015.06.211},
  volume       = {648},
  year         = {2015},
}