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- Wang, Z, et al.
(author)
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The boundary phase and the melting of CaSiO3 and MgSiO3 perovskites
- 2000
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In: JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0022-3697. ; 61:11, s. 1815-1820
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Journal article (peer-reviewed)abstract
- We have investigated the melting temperatures of MgSiO3 and CaSiO3 perovskites at high pressure conditions, using an empirical melting equation, combined with the assumption of a boundary phase existing at the melting point. This study indicates that both
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3. |
- Tomic, S., et al.
(author)
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Influence of conduction-band nonparabolicity on electron confinement and effective mass in GaNxAs1−x∕GaAs quantum wells
- 2004
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69, s. 245305-
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Journal article (peer-reviewed)abstract
- We derive an analytical model to describe the conduction-band states of GaNAs-based quantum well structures, including the band anticrossing effect between N resonant states and the conduction-band edge. The predictions of the model are compared to those obtained using a full ten-band k·p model based on the same set of parameters. Both methods are then tested by comparison with the experimentally determined ground- and excited-state interband transition energies of GaNxAs1−x quantum wells of different well widths and N composition x obtained at 300 K and under hydrostatic pressures up to 2.0 GPa . We show that the transition energies can be described by a consistent set of material parameters in all the samples studied, and present how the conduction to valence-band offset ratio varies strongly with x in GaNxAs1−x∕GaAs quantum well structures. We conclude that the model presented can be used to predict the transition energies and electron subband structure of any GaNxAs1−x∕GaAs quantum well with well width between 2 and 25 nm , and N composition x between 1 and 4% , although further work is still required to confirm the optimum choice for the variation of band offset ratio with composition.
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4. |
- Wang, Z, et al.
(author)
-
The boundary phase and the melting of CaSiO3 and MgSiO3 perovskites
- 2000
-
In: Journal of Physics and Chemistry of Solids. - 0022-3697. ; 61:11, s. 1815-1820
-
Journal article (peer-reviewed)abstract
- We have investigated the melting temperatures of MgSiO3 and CaSiO3 perovskites at high pressure conditions, using an empirical melting equation, combined with the assumption of a boundary phase existing at the melting point. This study indicates that both CaSiO3 and MgSiO3 perovskites have a cubic structure near the melting boundary, and that the obtained melting temperatures are in good agreement with experimental measurements (Zerr et al., Geophys. Res. Lett. 24 (1998) 909; J.S. Sweeney, D.L. Heinz, High Pressure-Temperature Research: Properties of Earth and Planetary Materials, in: M.H. Manghnani, T. Yagi (Eds.), AGU, (1998) p. 185]. Additionally, our results reveal that CaSiO3 and MgSiO3 perovskites cannot cause a partial melting at the core-mantle boundary. Our calculation and assumption suggest that the Lindemann law is valid to estimate the melting temperatures of silicates as the silicate phases near the melting boundary are definitely determined and chosen.
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