Tunable metal-insulator transition in Nd1−xYxNiO3 (x = 0.3, 0.4) perovskites thin film at near room temperature
Tunable metal-insulator transition in Nd1−xYxNiO3 (x = 0.3, 0.4) perovskites thin film at near room temperature
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近室温下 Nd1−xYxNiO3 (x = 0.3, 0.4) 钙钛矿薄膜中的可调谐金属-绝缘体转变
DOI：
10.1063/1.4926917
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发表时间：
2015
影响因子：
4
通讯作者：
Ming Liu
中科院分区：
文献类型：
--
作者：
Tao Shao;Z. Qi;Yuyin Wang;Yuanyuan Li;Meijuan Yang;Yu Wang;Guobin Zhang;Ming Liu
金属-绝缘体转变(MIT)是由于稀土镍酸盐中的电荷歧化和晶格扭曲引起的。现有研究表明，稀土镍酸盐的MIT行为对外部应力/压力相当敏感，这为MIT应变工程提供了一条可行的途径。与施加外加应变不同，MIT还可以通过稀土阳离子混合进行调制，这可以被视为本征量子应力。我们选择了Nd1-xYxNiO_3(x=0.3，0.4)钙钛矿薄膜作为原型系统，在近室温下实现了可调谐的尖峰MIT。通过调节Y的浓度，薄膜的转变温度可以在340-360K范围内变化。利用X射线衍射、X射线吸收谱(XAFS)和原位红外光谱研究了薄膜的结构和光学性质随组成和温度的变化。在麻省理工学院，红外传输强度随着温度的升高而减小，表明有明显的热色效应。同时，XAFS结果表明，随着Y原子的掺入和MIT相变，晶体原子结构发生了变化。Y原子的重掺杂导致了前缘峰的下降和Ni-O键的伸长，表明电荷歧化作用增强，Ni-3d和O-2p轨道间的杂化作用减弱。(C)2015 AIP出版有限责任公司。
Metal-insulator transition (MIT) occurs due to the charge disproportionation and lattice distortions in rare-earth nickelates. Existing studies revealed that the MIT behavior of rare-earth nickelates is fairly sensitive to external stress/pressure, suggesting a viable route for MIT strain engineering. Unlike applying extrinsic strain, the MIT can also be modulated by through rare-earth cation mixing, which can be viewed as intrinsic quantum stress. We choose Nd1-xYxNiO3 (x = 0.3, 0.4) perovskites thin films as a prototype system to exhibit the tunable sharp MIT at near room temperature. By adjusting Y concentration, the transition temperature of the thin films can be changed within the range of 340-360 K. X-ray diffraction, X-ray absorption tine structure (XAFS), and in situ infrared spectroscopy are employed to probe the structural and optical property variation affected by composition and temperature. The infrared transmission intensity decreases with temperature across the MIT, indicating a pronounced thermochromic effect. Meanwhile, the XAFS result exhibits that the crystal atomistic structure changes accompanying with the Y atoms incorporation and MIT phase transition. The heavily doped Y atoms result in the pre-edge peak descent and Ni-O bond elongation, suggesting an enhanced charge disproportionation effect and the weakening of hybridization between Ni-3d and O-2p orbits. (C) 2015 AIP Publishing LLC.