Charge Writing at the LaAlO3/SrTiO3 Surface

Biased conducting-up atomic force microscopy (AFM) has been shown to write and erase nanoscale metallic lines at the LaAlO3/SrTiO3 interface Using various AFM modes, we show the mechanism of conductivity switching is the writing of surface charge These charges are stably deposited on a wide range of LaAlO3 thicknesses, including bulk crystals. A strong asymmetry with writing polarity was found for 1 and 2 unit cells of LaAlO3, providing experimental evidence for a theoretically predicted built-in potential