"Structural Comparison of n-Type and p-Type LaAlO3/SrTiO3 Interfaces"

Ryosuke Yamamoto: Christopher Bell, Yasuyuki Hikita, Harold Y. Hwang, Hiroyuki Nakamura, Tsuyoshi Kimura, and Yusuke Wakabayashi; Phys. Rev. Lett., 07/15/11.

Additional Authors: Christopher Bell, Yasuyuki Hikita, Harold Y. Hwang, Hiroyuki Nakamura, Tsuyoshi Kimura, and Yusuke Wakabayashi

Abstract:

Using a surface x-ray diffraction technique, we investigated the atomic structure of two types of interfaces between LaAlO3 and SrTiO3, that is, p-type (SrO/AlO2) and n-type (TiO2/LaO) interfaces. Our results demonstrate that the SrTiO3 in the sample with the n-type interface has a large polarized region, while that with the p-type interface has a limited polarized region. In addition, atomic intermixing was observed to extend deeper into the SrTiO3 substrate at the n-type interface compared to the p type. These differences result in distinct degrees of band bending, which likely contributes to the striking contrast in electrical conductivity between the two types of interfaces.