Seebeck effect in the conducting LaAlO3/SrTiO3 interface
Seebeck effect in the conducting LaAlO3/SrTiO3 interface
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DOI：
10.1103/physrevb.81.085414
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发表时间：
2010-02-01
影响因子：
3.7
通讯作者：
Triscone, J. -M.
中科院分区：
文献类型：
--
作者：
Pallecchi, I.;Codda, M.;Triscone, J. -M.
在绝缘氧化物之间的界面处的金属行为的观察引发了全世界的努力，以阐明这些系统的物理学，并澄清一些仍然悬而未决的问题，其中包括导电系统的尺寸特性。为了解决这个问题，我们测量电输运（塞贝克效应，霍尔效应，电导率）在LaAlO 3/SrTiO 3接口，并进行比较，在掺杂SrTiO 3大块单晶。在这些实验中，使用背栅几何形状中的场效应来调谐载流子浓度。在77 K下的所有实验数据的综合分析表明，导电层的厚度是类似于7 nm和塞贝克效应的数据很好地描述了一个二维的态密度。我们发现背栅电压不仅对改变电荷密度而且对改变导电层的厚度都是有效的，在77 K下使用-4和+4 MV/m之间的电场时，导电层的厚度被发现以近似2的因子改变。没有增强的塞贝克效应，由于电子限制和没有证据的二维量子化步骤观察到的接口。
The observation of metallic behavior at the interface between insulating oxides has triggered worldwide efforts to shed light on the physics of these systems and clarify some still open issues, among which the dimensional character of the conducting system. In order to address this issue, we measure electrical transport (Seebeck effect, Hall effect, and conductivity) in LaAlO3/SrTiO3 interfaces and, for comparison, in a doped SrTiO3 bulk single crystal. In these experiments, the carrier concentration is tuned, using the field effect in a back-gate geometry. The combined analysis of all experimental data at 77 K indicates that the thickness of the conducting layer is similar to 7 nm and that the Seebeck-effect data are well described by a two-dimensional density of states. We find that the back-gate voltage is effective in varying not only the charge density but also the thickness of the conducting layer, which is found to change by a factor of similar to 2, using an electric field between -4 and + 4 MV/m at 77 K. No enhancement of the Seebeck effect due to the electronic confinement and no evidence for two-dimensional quantization steps are observed at the interfaces.