Fabrication of Conductive Quantum Wire by using Dislocation Array

利用金属掺杂在绝缘态氧化镁双晶晶界(GB)中沿位错核的高温偏析行为制备了导电量子线，并用扫描电子显微镜(STEM)和第一性原理计算对其进行了表征。STEM图像和电子能量损失谱(EELS)图谱表明，在MgO GB中形成了一个结构单元来补偿晶格失配，钙(Ca)和钛(Ti)杂质在GB中有很强的局域化。第一性原理计算表明，偏析的钛原子沿晶界形成导电沟道，表现为类似半导体的行为。利用位错核的自分离行为，我们证明了在绝缘固体晶体中制备具有特定电子性质的低维量子结构。

In this work, a conductive quantum wire was fabricated by using high-temperature segregation behavior of a metallic dopant along a dislocation core in an insulating MgO bicrystal grain boundary (GB) and then was characterized by a scanning TEM (STEM) and a first-principle calculation. The STEM image and electron energy loss spectrum (EELS) mapping showed that a structure unit in the MgO GB is formed to compensate lattice mismatch and calcium (Ca) and titanium (Ti) impurities are strongly localized in the GB. The first-principle calculation revealed that the segregated Ti atoms form conductive channels along the GB suggesting semi-conductor like behavior. By using self-segregation behavior along a dislocation core, we demonstrated to fabricate a low dimensional quantum structure with a specific electronic property in an insulating solid crystal.