Anomalous response to gate voltage application in mesoscopic LaAlO_3/SrTiO_3 devices

Abstract

We report on resistivity and Hall measurements performed on a series of narrow mesa devices fabricated from LaAlO_3/SrTiO_3 single interface heterostructure with a bridge width range of 1.5-10 microns. Upon applying back-gate voltage of the order of a few Volts, a strong increase in the sample resistance (up to factor of 35) is observed, suggesting a relatively large capacitance between the Hall-bar and the gate. The high value of this capacitance is due to the device geometry, and can be explained within an electrostatic model using the Thomas Fermi approximation. The Hall coefficient is sometimes a non-monotonic function of the gate voltage. This behavior is inconsistent with a single conduction band model. We show that a theoretical two-band model is consistent with this transport behavior, and indicates a metal to insulator transition in at least one of these bands.

5 pages, 4 figures

References in corpus (5)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Avoiding the polarization catastrophe in LaAlO3 overlayers on SrTiO3(001) through a polar distortion
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$

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• Magneto-transport study of top- and back-gated LaAlO${}_3$/SrTiO${}_3$ heterostructures
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• Ferroelectric Exchange Bias Affects Interfacial Electronic States
• Tunneling into a quantum confinement created by a single-step nano-lithography of conducting oxide interfaces
• The mechanism of spin-orbit coupling in a 2D oxide interface
• Gate-tunable, normally-on to normally-off memristance transition in patterned LaAlO3/SrTiO3 interfaces
• Transport and thermoelectric properties of the LaAlO${}_3$/SrTiO${}_3$ interface
• Electronic transport in sub-micrometric channels at the LaAlO${}_3$/SrTiO${}_3$ interface