First-principles equation of state and phase stability of niobium pentoxide
First-principles equation of state and phase stability of niobium pentoxide
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DOI：
10.1016/j.commatsci.2013.07.032
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发表时间：
2014
影响因子：
3.3
通讯作者：
C. Valencia-Balvín;S. Pérez-Walton;G. Dalpian;J. Osorio-Guillén
中科院分区：
文献类型：
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作者：
C. Valencia-Balvín;S. Pérez-Walton;G. Dalpian;J. Osorio-Guillén
五氧化二铌是一种多态宽禁带半导体，具有良好的介电性能，使其成为技术应用中的重要材料。尽管其意义重大，但目前尚未对其相稳定性和多晶型性进行理论研究。我们研究了压力下 Nb2O5 几个相的能量学和相稳定性。状态方程、等温体积模量和平衡晶体结构是根据压力高达 100 kbar 的第一原理密度泛函理论计算的。状态方程表明，零压力下稳定的晶体结构是 H 相，然后，在 0.24 kbar 时发生晶体相变到 B 相。此外，结果表明，在研究的压力范围内，B 相仍然是唯一的高压稳定相。
Niobium pentoxide is a polymorphic wide-gap semiconductor with good dielectric properties that make it an important material in technological applications. In spite of its significance, there are not theoretical studies of its phase stability and polymorphism. We have investigated the energetics and phase stability of several phases of Nb2O5under pressure. The equation of state, the isothermal bulk moduli and the equilibrium crystal structures have been calculated from first-principles density functional theory for pressures up to 100 kbar. The equation of state reveals that the stable crystalline structure at zero pressure is the H phase, then, a crystallographic phase transition takes place at 0.24 kbar to the B phase. Additionally, it is shown that in the pressure range studied the B phase remains as the sole high-pressure stable phase.