Anisotropic Electronic Transport of the Two-Dimensional Electron System in Al₂O₃ /SrTiO₃ Heterostructures
Anisotropic Electronic Transport of the Two-Dimensional Electron System in Al₂O₃ /SrTiO₃ Heterostructures
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DOI：
10.1103/physrevb.95.245132
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发表时间：
2017-05
影响因子：
3.7
通讯作者：
K. Wolff;R. Schafer;M. Meffert;D. Gerthsen;R. Schneider;D. Fuchs
中科院分区：
文献类型：
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作者：
K. Wolff;R. Schafer;M. Meffert;D. Gerthsen;R. Schneider;D. Fuchs
Al2O3 SrTiO3异质结构中二维电子系统的输运测量表明，在T = 30 K以下，Al2O3 SrTiO3异质结构具有显著的非晶各向异性行为。认为SrTiO3中的晶格位错和界面步骤是电子各向异性的主要来源。各向异性缺陷散射同样显著改变了低温下的磁电阻，并通过自旋弛豫的Elliot Yafet机制显著影响自旋-轨道耦合，导致各向异性弱局域化。施加平行于界面的磁场会产生额外的场诱导电导各向异性，这可归因于Rashba自旋轨道相互作用。与LaAlO3 SrTiO3相比，Rashba耦合似乎减少了，这表明Al2O3 SrTiO3异质结构中的极性较弱。
Transport measurements on the two dimensional electron system in Al2O3 SrTiO3 heterostructures indicate significant noncrystalline anisotropic behavior below T = 30 K. Lattice dislocations in SrTiO3 and interfacial steps are suggested to be the main sources for electronic anisotropy. Anisotropic defect scattering likewise alters magnetoresistance at low temperature remarkably and influences spin-orbit coupling significantly by the Elliot Yafet mechanism of spin relaxation resulting in anisotropic weak localization. Applying a magnetic field parallel to the interface results in an additional field induced anisotropy of the conductance, which can be attributed to Rashba spin orbit interaction. Compared to LaAlO3 SrTiO3, Rashba coupling seems to be reduced indicating a weaker polarity in Al2O3 SrTiO3 heterostructures.