Magnetotransport in high-mobility graphene antidot arrays

A. SANDNER; T. PREIS; PAULA GIUDICI; J. EROMS

Berlin

Congreso; 79. Jahrestagung der DPG und DPG-Frühjahrstagung; 2015

DPG

We report on the observation of antidot peaks in roh_xx in monolayer-graphene (MLG), encapsulated between hexagonal boron nitride (hBN). The hBN-MLG-hBN heterostructures were fabricated with a dry transfer pick-up technique; subsequently mesas were etched in Hall bar geometry and contacted with 1-dimensional side contacts [1]. The periodic antidot lattice was defined in a following step by additional electron-beam lithography and reactive ion etching (see fig. 1).We performed measurements on stacks with different antidot lattice periods down to 100 nm. Several peaks in magnetoresistance can be identified and assigned to orbits around one and several antidots (see fig. 2) [2]. This proves ballistic transport in our graphene heterostructures, in spite of the critical etching step for small lattice periods. We show measurements at different temperatures and can study antidot peaks down to very low carrier densities (n = 2*E11 cm-2) and magnetic fields (B = 0.5 T). At higher magnetic fields, well defined quantum Hall plateaus with filling factors down to nu = 1 are observed, even at an antidot period of 100 nm.