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arXiv 1710.08652cond-mat.mtrl-scicond-mat.str-el
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氧化物异质结构LaAlO3/SrTiO3中La间隙缺陷引起的绝缘体-金属转变

La interstitial defect-induced insulator-metal transition in oxide heterostructures LaAlO3/SrTiO3

Jun Zhou, Ming Yang, Yuan Ping Feng, Andrivo Rusydi

摘要:

过氧化氢氧化物界面因其基础物理和全氧化物电子学应用前景而引起了人们极大的研究兴趣。基于第一性原理计算,我们提出了LaAlO 3/SrTiO 3(110)中表面La间隙促进界面绝缘体-金属转变的新理论.与表面氧空位对LaAlO 3/SrTiO 3(001)界面的绝缘体-金属转变起决定性作用相比,我们发现表面La空位在实验上更接近实际,更易于操作,并且在大气环境中更稳定。有趣的是,这些表面La晶体在导电的LaAlO 3/SrTiO 3(110)界面上也诱导出具有Ti dyz/dxz特征的自旋分裂态。另一方面,对于绝缘的LaAlO 3/SrTiO 3(110)(<4个晶胞LaAlO 3厚度),在LaAlO 3侧发现La(Al)和O原子之间的畸变,部分地补偿了偏振发散。我们的研究结果揭示了LaAlO 3/SrTiO 3(110)异质结构中金属-绝缘体转变的起源,也揭示了LaAlO 3/SrTiO 3(110)异质结构在电子和磁性应用中的新的可能性。

英文摘要:

Perovskite oxide interfaces have attracted tremendous research interest for their fundamental physics and promising all-oxide electronics applications. Here, based on first-principles calculations, we propose a novel surface La interstitial promoted interface insulator-metal transition in LaAlO3/SrTiO3 (110). Compared with surface oxygen vacancies, which play a determining role on the insulator-metal transition of LaAlO3/SrTiO3 (001) interfaces, we find that surface La interstitials can be more experimentally realistic and accessible for manipulation and more stable in ambient atmospheric environment. Interestingly, these surface La interstitials also induce significant spin-splitting states with Ti dyz/dxz character at conducting LaAlO3/SrTiO3 (110) interface. On the other hand, for insulating LaAlO3/SrTiO3 (110) (<4 unit cells LaAlO3 thickness), a distortion between La (Al) and O atoms is found at the LaAlO3 side, partially compensating the polarization divergence. Our results reveal the origin of metal-insulator transition in LaAlO3/SrTiO3 (110) heterostructures, and also shed light on the manipulation of the superior properties of LaAlO3/SrTiO3 (110) for new possibilities of electronic and magnetic applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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