Top and Split Gating Control of the Electrical Characteristics of a Two-dimensional Electron Gas in a LaAlO3/SrTiO3 Perovskite
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A top gate field effect transistor was fabricated using polymethyl methacrylate (PMMA) as a gate insulator on a LaAlO3 (LAO)/SrTiO3 (STO) hetero-interface. It showed n-type behavior, and a depletion mode was observed at low temperature. The electronic properties of the 2-dimensional electron gas at the LAO/STO hetero-interface were not changed by covering LAO with PMMA following the Au top gate electrode. A split gate device was also fabricated to construct depletion mode by using a narrow constriction between the LAO/STO conduction interface. The depletion mode, as well as superconducting critical current, could be controlled by applying a split gate voltage. Noticeably, the superconducting critical current tended to decrease with decreasing the split gate voltage and finally became zero. These results indicate that a weak-linked Josephson junction can be constructed and destroyed by split gating. This observation opens the possibility of gate-voltage-adjustable quantum devices.
KeywordsTop gating Split gating 2-DEGS Perovskite Hetero-interface
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- D. A. Dikin, M. Mehta, C. W. Bark, C. M. Folkman, C. B. Eom and V. Chandrasekhar, AIP Conf. Proc. 1393, 347 (2011).Google Scholar