School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Institute of Nuclear Physics and Chemistry, Chinese Academy of Engineering Physics, Mianyang, 621900, China.
Sci Rep. 2017 Jul 25;7(1):6399. doi: 10.1038/s41598-017-06725-8.
In this study, a density functional theory method is employed to investigate the effects of isovalent and aliovalent substitution of Sm on the phase stability, thermo-physical properties and electronic structure of GdZrO. It is shown that the isovalent substitution of Sm for Gd results in the formation of GdZrO-SmZrO solid solution, which retains the pyrochlore structure and has slight effects on the elastic moduli, ductility, Debye temperature and band gap of GdZrO. As for the aliovalent substitution of Sm for Zr site, a pyrochlore-to-defect fluorite structural transition is induced, and the mechanical, thermal properties and electronic structures are influenced significantly. As compared with the GdZrO, the resulted GdSmZrO compositions have much smaller elastic moduli, better ductility and smaller Debye temperature. Especially, an amount of electrons distribute on the fermi level and they are expected to have larger thermal conductivity than GdZrO. This study suggests an alternative way to engineer the thermo-physical properties of GdZrO and will be beneficial for its applications under stress and high temperature.
在这项研究中，采用密度泛函理论方法研究了等电子和变价替代 Sm 对 GdZrO 的相稳定性、热物理性质和电子结构的影响。结果表明，Sm 对 Gd 的等电子替代导致形成 GdZrO-SmZrO 固溶体，其保留萤石结构，对 GdZrO 的弹性模量、延展性、德拜温度和带隙影响很小。而对于 Sm 替代 Zr 位的变价替代，则会引起萤石到缺陷萤石结构的转变，从而显著影响机械、热性能和电子结构。与 GdZrO 相比，生成的 GdSmZrO 具有更小的弹性模量、更好的延展性和更小的德拜温度。特别是，一些电子分布在费米能级上，它们有望具有比 GdZrO 更大的热导率。本研究为调控 GdZrO 的热物理性质提供了一种替代方法，有助于其在高压和高温下的应用。
