Abstract
Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO3/SrTiO3 interface 2DEG at the nanoscale. In particular, SrTiO3 domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO3 twin boundary and detect a change in LaAlO3/SrTiO3 interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO3 domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO3-based devices on the nanoscale.
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Acknowledgements
Y.F., N.H., Y.S. and B.K. were supported by the European Research Council grant ERC-2014-STG-639792 and Israel Science Foundation grant ISF-1102/13 and ISF-1281/17. Z.C., Y.H. and H.Y.H. acknowledge support by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract DE-AC02–76SF00515 (Y.H.), and the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant GBMF4415 (Z.C.). E.K.H.S. was supported by EPSRC grant EP/P024904/1.
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Y.F., Y.S. and B.K. designed the experiment and performed the measurements. C.B., Y.X., Z.C., Y.H. and H.Y.H. provided the samples, N.H. contributed to the simulations and E.K.H.S. contributed to the interpretation of the data. Y.F. and B.K. prepared the manuscript with input from all co-authors.
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Frenkel, Y., Haham, N., Shperber, Y. et al. Imaging and tuning polarity at SrTiO3 domain walls. Nature Mater 16, 1203–1208 (2017). https://doi.org/10.1038/nmat4966
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DOI: https://doi.org/10.1038/nmat4966
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