The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel gamma-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1E15 cm-2. Herein, we report on the patterning of 2DEG at the gamma-Al2O3/SrTiO3 interface grown at 650 {\deg}C by pulsed laser deposition using a hard mask of LaMnO3. The patterned 2DEG exhibits a critical thickness of 2 unit cells of gamma-Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3E13 cm-2, much lower than that of the unpatterned sample (1E15 cm-2). Remarkably, a high electron mobility of approximately 3,600 cm2V-1s-1 was obtained at low temperatures for the patterned 2DEG at a carrier density of 7E12 cm-2, which exhibits clear Shubnikov-de Hass quantum oscillations. The patterned high-mobility 2DEG at the gamma-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devices.
@article{arxiv.1706.09235,
title = {Suppressed carrier density for the patterned high mobility two-dimensional electron gas at gamma-Al2O3/SrTiO3 heterointerfaces},
author = {W. Niu and Y. L. Gan and Y. Zhang and D. V. Christensen and M. von Soosten and X. F. Wang and Y. B. Xu and R. Zhang and N. Pryds and Y. Z. Chen},
journal= {arXiv preprint arXiv:1706.09235},
year = {2017}
}