Yoshimatsu K, Yasuhara R, Kumigashira H, Oshima M
Department of Applied Chemistry, University of Tokyo, Tokyo 113-8656, Japan.
Phys Rev Lett. 2008 Jul 11;101(2):026802. doi: 10.1103/PhysRevLett.101.026802. Epub 2008 Jul 9.
We have studied the electronic structure at the heterointerface between the band insulators LaAlO3 and SrTiO3 using in situ photoemission spectroscopy. Our experimental results clearly reveal the formation of a notched structure on the SrTiO3 side due to band bending at the metallic LaAlO3/TiO2-SrTiO3 interface. The structure, however, is absent at the insulating LaAlO3/SrO-SrTiO3 interface. The present results indicate that the metallic states originate not from the charge transfer through the interface on a short-range scale but from the accumulation of carriers on a long-range scale.
我们使用原位光电子能谱研究了带绝缘体LaAlO3和SrTiO3之间异质界面的电子结构。我们的实验结果清楚地表明，由于金属LaAlO3/TiO2 - SrTiO3界面处的能带弯曲，在SrTiO3一侧形成了一个缺口结构。然而，在绝缘的LaAlO3/SrO - SrTiO3界面处不存在该结构。目前的结果表明，金属态并非源于短程尺度上通过界面的电荷转移，而是源于长程尺度上载流子的积累。
