论文标题
重新审视复杂氧化物薄膜的应变游戏：pbtio $ _3 $中的基材 - 材料 - 影片热膨胀不匹配
Strain game revisited for complex oxide thin-films: Substrate-film thermal expansion mismatch in PbTiO$_3$
论文作者
论文摘要
材料特性，尤其是钙钛矿氧化物对外延菌株的敏感性已得到充分利用，以创建具有新特性或增强特性的材料。尽管当然已经认识到，散装和底物材料的热膨胀系数的不匹配将导致不合适的菌株，但这种贡献对铁电钙钛矿薄膜的重要性尚未系统地探索。我们使用第一原理密度功能理论和各种基质上的铁电pbtio $ _3 $薄膜的示例，以表明忽略底物的热膨胀（即，假设膜的平面内晶格参数仍然是在温度上大致构成的典型范围，而构成了质量的质量，则在膜上的平面内晶格参数仍然存在，而构成了质量的质量，而这些趋势是在质量上既定的，而这些趋势是构成了质量的质量，那么该趋势的范围是构成的质量，而这些潮流的范围是造成的。不匹配已正确考虑。我们的工作表明，定义为单个数字的不合适菌株的概念对于pbtio $ _3 $特别不明，并邀请进一步研究其他薄膜材料中热膨胀不匹配与结构和功能性能之间的相互作用。
The sensitivity of materials properties, particularly those of perovskite oxides, to epitaxial strain has been exploited to great advantage to create materials with new or enhanced properties. Although it has certainly been recognized that mismatch in the thermal expansion coefficients of the bulk and substrate material will contribute to the misfit strain, the significance of this contribution for ferroelectric perovskite thin-films has not been systematically explored. We use first-principles density functional theory and the example of ferroelectric PbTiO$_3$ thin-films on various substrates to show that ignoring the thermal expansion of the substrate (that is, assuming that the in-plane lattice parameter of the film remains roughly constant as a function of temperature) results in ferroelectric transition temperatures and structural trends that are completely qualitatively different from calculations in which thermal expansion mismatch is properly taken into account. Our work suggests that the concept of a misfit strain defined as a single number is particularly ill-defined for PbTiO$_3$ and invites further study of the interplay between thermal expansion mismatch and structural and functional properties in other thin-film materials.
