Correction to: Nature Nanotechnology, published online 5 February 2018.

In the version of this Letter originally published, in two instances in Fig. 1 the layers in the cross-sectional view of the (001) interface were incorrectly labelled: in Fig. 1b SrO+ should have read SrO0; in Fig. 1c LaO+, AlO2, LaO+, TiO20, SrO+, TiO20 should have read LaO33–, Al3+, LaO33–, Ti4+, SrO34–, Ti4+. In Fig. 3c the upper-right equation read –σs = –e/2a2 but should have read –σs = e/2a2 and in Fig. 3f the lower-right equation read –σs = –e/2√3a2 but should have read σs = –e/2√3a2. In addition, in the HTML version the affiliation 'Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea' was mistakenly listed as the present address of S.-Y.C. but should have been listed as an affiliation for K.S., B.P., J.K.L., S.-Y.C. and S.H.O. And, in the Supplementary Information file, the text 'small compared with the' was mistakenly added to the beginning of the title. These errors have now been corrected in the online version of the Letter.