Towards Two-Dimensional Metallic Behavior at LaAlO3/SrTiO3 Interfaces
Towards Two-Dimensional Metallic Behavior at LaAlO3/SrTiO3 Interfaces
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DOI：
10.1103/physrevlett.102.216804
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发表时间：
2009-05-29
影响因子：
8.6
通讯作者：
Barthelemy, A.
中科院分区：
文献类型：
--
作者：
Copie, O.;Garcia, V.;Barthelemy, A.
使用低温导电尖端原子力显微镜的横截面几何形状，我们表征了在 LaAlO3 和 SrTiO3 之间的界面处形成的金属电子气的局部传输特性。在低温下，我们发现载流子不会从界面扩散开，而是被限制在大约 10 nm 的范围内，就像在室温下一样。模拟考虑了 SrTiO3 介电常数对温度和电场的较大依赖性，预测片状载流子密度大于约 6x10(13) cm(-2) 时，限制在几纳米范围内。我们讨论多频带载波系统的实验和仿真结果。值得注意的是，根据霍尔测量估计的费米波长与 16 nm 相似，表明电子气处于二维边缘。
Using a low-temperature conductive-tip atomic force microscope in cross-section geometry we have characterized the local transport properties of the metallic electron gas that forms at the interface between LaAlO3 and SrTiO3. At low temperature, we find that the carriers do not spread away from the interface but are confined within similar to 10 nm, just like at room temperature. Simulations taking into account both the large temperature and electric-field dependence of the permittivity of SrTiO3 predict a confinement over a few nm for sheet carrier densities larger than similar to 6x10(13) cm(-2). We discuss the experimental and simulations results in terms of a multiband carrier system. Remarkably, the Fermi wavelength estimated from Hall measurements is similar to 16 nm, indicating that the electron gas in on the verge of two dimensionality.