Assessment of Strain-Generated Oxygen Vacancies Using SrTiO3 Bicrystals
Assessment of Strain-Generated Oxygen Vacancies Using SrTiO3 Bicrystals
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DOI：
10.1021/acs.nanolett.5b01245
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发表时间：
2015-06-01
期刊：
影响因子：
10.8
通讯作者：
Ikuhara, Yuichi
中科院分区：
文献类型：
--
作者：
Choi, Si-Young;Kim, Sung-Dae;Ikuhara, Yuichi
原子级缺陷强烈影响材料的电学和光学性质，并且它们的影响在局部尺寸中可能更加明显。在这里，我们直接表明，应变触发的复杂氧化物中的氧空位的形成通过检查SrTiO 3双晶的倾斜边界。通过透射电子显微镜和电子能量损失谱，我们确定了应变沿着的倾斜边界和氧空位之间的位错核心的应变施加区域。第一性原理计算支持的应变，无论其类型或符号，降低氧空位的形成能，从而提高空位的形成。最后，电流-电压测量证实，这种氧空位在应变边界的I-V曲线的非线性以及电阻率的降低。我们的研究结果强烈表明，氧空位优先形成，并在应变积累的区域，如异质界面和晶界偏聚。
Atomic-scale defects strongly influence the electrical and optical properties of materials, and their impact can be more pronounced in localized dimensions. Here, we directly demonstrate that strain triggers the formation of oxygen vacancies in complex oxides by examining the tilt boundary of SrTiO3 bicrystals. Through transmission electron microscopy and electron energy loss spectroscopy, we identify strains along the tilt boundary and oxygen vacancies in the strain-imposed regions between dislocation cores. First-principles calculations support that strains, irrespective of their type or sign, lower the formation energy of oxygen vacancies, thereby enhancing vacancy formation. Finally, current-voltage measurements confirm that such oxygen vacancies at the strained boundary result in a decrease of the nonlinearity of the I-V curve as well as the resistivity. Our results strongly indicate that oxygen vacancies are preferentially formed and are segregated at the regions where strains accumulate, such as heterogeneous interfaces and grain boundaries.