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arXiv · 1706.09235

Suppressed carrier density for the patterned high mobility two-dimensional electron gas at gamma-Al2O3/SrTiO3 heterointerfaces

W. Niu·Y. L. Gan·Y. Zhang·D. V. Christensen·M. von Soosten·X. F. Wang·Y. B. Xu·R. Zhang·N. Pryds·Y. Z. Chen
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Abstract

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.

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W. Niu, Y. L. Gan, Y. Zhang, D. V. Christensen, M. von Soosten, X. F. Wang, Y. B. Xu, R. Zhang, N. Pryds, Y. Z. Chen. 2017-06-28. Suppressed carrier density for the patterned high mobility two-dimensional electron gas at gamma-Al2O3/SrTiO3 heterointerfaces. https://doi.org/10.1063/1.4993165

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