Dielectric collapse at the LaAlO3/SrTiO3 (001) heterointerface under applied electric field

Makoto Minohara, Yasuyuki Hikita, Christopher Bell, Hisashi Inoue, Masayuki Hosoda, H. K. Sato, Hiroshi Kumigashira, Masaharu Oshima, E Ikenaga, Harold Y. Hwang

Research output: Contribution to journalArticle (Academic Journal)

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The fascinating interfacial transport properties at the LaAlO3/SrTiO3 heterointerface have led to intense investigations of this oxide system. Exploiting the large dielectric constant of SrTiO3 at low temperatures, tunability in the interfacial conductivity over a wide range has been demonstrated using a back-gate device geometry. In order to understand the effect of back-gating, it is crucial to assess the interface band structure and its evolution with external bias. In this study, we report measurements of the gate-bias dependent interface band alignment, especially the confining potential profile, at the conducting LaAlO3/SrTiO3 (001) heterointerface using soft and hard x-ray photoemission spectroscopy in conjunction with detailed model simulations. Depth-profiling analysis incorporating the electric field dependent dielectric constant in SrTiO3 reveals that a significant potential drop on the SrTiO3 side of the interface occurs within ~ 2 nm of the interface under negative gate-bias. These results demonstrate gate control of the collapse of the dielectric permittivity at the interface, and explain the dramatic loss of electron mobility with back-gate depletion.
Original languageEnglish
Article number9516
Number of pages7
JournalScientific Reports
Publication statusPublished - 25 Aug 2017

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