Thickness-dependent local surface electronic structures of homoepitaxial SrTiO3 thin films

T. Ohsawa; K. Iwaya; R. Shimizu; T. Hashizume; T. Hitosugi

doi:10.1063/1.3485826

Thickness-dependent local surface electronic structures of homoepitaxial SrTiO₃ thin films

T. Ohsawa, K. Iwaya, R. Shimizu, T. Hashizume, T. Hitosugi

Research output: Contribution to journal › Article › peer-review

28 Citations (Scopus)

Abstract

We have investigated the atomically-resolved substrate and homoepitaxial thin film surfaces of SrTiO₃ (001) using low-temperature scanning tunneling microscopy/scanning tunneling spectroscopy (STS) combined with pulsed laser deposition. It was found that a typical annealing treatment for preparation of SrTiO₃ substrates, unexpectedly, resulted in a disordered surface on an atomic scale. In contrast, homoepitaxial SrTiO ₃ thin films grown on this disordered substrate exhibited a (2×2) surface reconstruction. The STS measurements revealed a number of surface defects in a 10 unit cell thick SrTiO₃ film but much fewer in a 50 unit cell thick film, indicating nonuniform stoichiometry along the growth direction. These results suggest the possibility of using homoepitaxial SrTiO₃ film surfaces as idealized substrates, opening a way to extract novel functionalities in complex oxides heterostructures.

Original language	English
Article number	073710
Journal	Journal of Applied Physics
Volume	108
Issue number	7
DOIs	https://doi.org/10.1063/1.3485826
Publication status	Published - 2010 Oct 1

ASJC Scopus subject areas

Physics and Astronomy(all)

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title = "Thickness-dependent local surface electronic structures of homoepitaxial SrTiO3 thin films",

abstract = "We have investigated the atomically-resolved substrate and homoepitaxial thin film surfaces of SrTiO3 (001) using low-temperature scanning tunneling microscopy/scanning tunneling spectroscopy (STS) combined with pulsed laser deposition. It was found that a typical annealing treatment for preparation of SrTiO3 substrates, unexpectedly, resulted in a disordered surface on an atomic scale. In contrast, homoepitaxial SrTiO 3 thin films grown on this disordered substrate exhibited a (2×2) surface reconstruction. The STS measurements revealed a number of surface defects in a 10 unit cell thick SrTiO3 film but much fewer in a 50 unit cell thick film, indicating nonuniform stoichiometry along the growth direction. These results suggest the possibility of using homoepitaxial SrTiO3 film surfaces as idealized substrates, opening a way to extract novel functionalities in complex oxides heterostructures.",

author = "T. Ohsawa and K. Iwaya and R. Shimizu and T. Hashizume and T. Hitosugi",

note = "Funding Information: This study was supported by the World Premier Research Institute Initiative, promoted by the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT) for the Advanced Institute for Materials Research, Tohoku University, Japan. This work was financially supported by a Grant-in-Aid for Young Scientists (B), (grant no. 22760021), MEXT, Japan.",

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AU - Ohsawa, T.

AU - Iwaya, K.

AU - Shimizu, R.

AU - Hashizume, T.

AU - Hitosugi, T.

N1 - Funding Information: This study was supported by the World Premier Research Institute Initiative, promoted by the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT) for the Advanced Institute for Materials Research, Tohoku University, Japan. This work was financially supported by a Grant-in-Aid for Young Scientists (B), (grant no. 22760021), MEXT, Japan.

PY - 2010/10/1

Y1 - 2010/10/1

N2 - We have investigated the atomically-resolved substrate and homoepitaxial thin film surfaces of SrTiO3 (001) using low-temperature scanning tunneling microscopy/scanning tunneling spectroscopy (STS) combined with pulsed laser deposition. It was found that a typical annealing treatment for preparation of SrTiO3 substrates, unexpectedly, resulted in a disordered surface on an atomic scale. In contrast, homoepitaxial SrTiO 3 thin films grown on this disordered substrate exhibited a (2×2) surface reconstruction. The STS measurements revealed a number of surface defects in a 10 unit cell thick SrTiO3 film but much fewer in a 50 unit cell thick film, indicating nonuniform stoichiometry along the growth direction. These results suggest the possibility of using homoepitaxial SrTiO3 film surfaces as idealized substrates, opening a way to extract novel functionalities in complex oxides heterostructures.

AB - We have investigated the atomically-resolved substrate and homoepitaxial thin film surfaces of SrTiO3 (001) using low-temperature scanning tunneling microscopy/scanning tunneling spectroscopy (STS) combined with pulsed laser deposition. It was found that a typical annealing treatment for preparation of SrTiO3 substrates, unexpectedly, resulted in a disordered surface on an atomic scale. In contrast, homoepitaxial SrTiO 3 thin films grown on this disordered substrate exhibited a (2×2) surface reconstruction. The STS measurements revealed a number of surface defects in a 10 unit cell thick SrTiO3 film but much fewer in a 50 unit cell thick film, indicating nonuniform stoichiometry along the growth direction. These results suggest the possibility of using homoepitaxial SrTiO3 film surfaces as idealized substrates, opening a way to extract novel functionalities in complex oxides heterostructures.

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Thickness-dependent local surface electronic structures of homoepitaxial SrTiO₃ thin films

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