Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 8: Transport and theory of electronic structure

HL 8.5: Vortrag

Montag, 1. April 2019, 16:00–16:15, H33

Surface acoustic wave induced electrical current in graphene — •Pai Zhao, Lars Tiemann, and Robert H. Blick — Center for Hybrid Nanostructures, Hamburg University, 22761 Hamburg, Germany

Surface acoustic waves (SAWs) generated on a piezoelectric substrate are able to induce an acoustoelectric current that sweeps electrons along with the propagating waves.[1,2] Here, we show how to apply this acoustoelectric current as an alternative to a conventional current to study magnetotransport in monolayer graphene. We fabricated a pair of interdigitated transducers (IDTs) on a semi-insulating GaAs substrate, separated by 1,800 µm. A large CVD graphene sheet was transferred from a copper substrate onto the GaAs sample. In a photolithographic process we patterned a Hall bar structure centered between the two IDTs. Regular magnetotransport characterization of the graphene sample shows an intrinsic carrier concentration of 5.5×1011cm−2 and a mobility of 600cm2/Vs. When the IDTs on the GaAs are excited at one of their harmonic resonance frequencies, we detect an acoustoelectric current passing through the graphene Hall bar, which follows the longitudinal resistance oscillations with magnetic fields up to 8 Tesla at 4.2 Kelvin.

[1] A. Wixforth et al., Phys. Rev. Lett 56, 2104 (1986).

[2] D. Kreft et al., Phys. Rev. B 94, 235305 (2016).

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