Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 12: Graphene: Transport
(Joint session of DS, DY, HL, MA, O and TT organized by HL)

TT 12.8: Vortrag

Montag, 7. März 2016, 17:15–17:30, H17

Acoutoelectric currents in coated graphene on SiC — •Alberto Hernández-Mínguez, Abbes Taharoui, Marcelo Lopes, and Paulo Santos — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany

Surface acoustic waves (SAWs) provide useful mechanisms for the dynamic modulation and transport of carriers in two-dimensional semiconductor heterostructures. In the case of graphene, we have recently shown that the piezoelectric fields accompanying SAWs can induce unipolar electric currents in lithographically patterned graphene layers grown on SiC. Due to the weak piezoelectricity of SiC, however, the interaction between SAW and carriers in graphene is relatively small. Future applications of the acoustic transport require the generation of strong SAWs for their efficient coupling to graphene, as well as the control of the density and type of carriers transported by the SAW. In this contribution, we study structures for efficient generation of high frequency acoustic transport (> 1 GHz) in graphene grown on SiC that are also compatible with top gates for the electric control of the carrier density. Several Rayleigh modes with frequencies up to 7 GHz are efficiently generated in our structure, inducing acoustic currents for the fundamental frequency that are 300 times larger than the ones reported in our previous devices. These results are an important step towards the dynamic control of carriers in graphene at the sub-micrometer regime, as well as for the dynamic manipulation of the electron spin by strain-induced gauge fields.