Reconfigurable edge-state engineering in graphene using LaAlO$_3$/SrTiO$_3$ nanostructures. (arXiv:1811.02030v1 [cond-mat.mes-hall])

//Reconfigurable edge-state engineering in graphene using LaAlO$_3$/SrTiO$_3$ nanostructures. (arXiv:1811.02030v1 [cond-mat.mes-hall])

The properties of graphene depend sensitively on doping with respect to the charge-neutrality point (CNP). Tuning the CNP usually requires electrical gating or chemical doping. Here, we describe a technique to reversibly control the CNP in graphene with nanoscale precision, utilizing LaAlO$_3$/SrTiO$_3$ (LAO/STO) heterostructures and conductive atomic force microscope (c-AFM) lithography. The local electron density and resulting conductivity of the LAO/STO interface can be patterned with a conductive AFM tip, and placed within two nanometers of an active graphene device. The proximal LAO/STO nanostructures shift the position of graphene CNP by ~ $10^{12}$ cm$^{-2}$, and are also gateable. Here we use this effect to create reconfigurable edge states in graphene, which are probed using the quantum Hall effect. Quantized resistance plateaus at $h/e^2$ and $h/3e^2$ are observed in a split Hall device, demonstrating edge transport along the c-AFM written edge that depends on the polarity of both the magnetic field and direction of currents. This technique can be readily extended to other device geometries.

Published : "arXiv Mesoscale and Nanoscale Physics".

2018-11-07T04:30:19+00:00November 7th, 2018|Categories: Publications|Tags: , |
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