Fig. 4: A 2D interface of soft- and hard- matter.
From: Soft-matter-induced orderings in a solid-state van der Waals heterostructure
a SEM image of the DNA origami 2D film on top of the pre-patterned bottom Au gate covered by 15 nm Al2O3. The DNA 2D film is outlined by the white dashed line. b Device fabrication of a typical vertical heterostructure of BN(20–30 nm)/graphene/BN(1–3 layer) on top of the DNA film in (a). The electrodes are patterned using standard lithography followed by metallization. Hall bars of the heterostructure are patterned via plasma etching. c Cartoon illustration of the vdW heterostructure. d Landau fan map (log(Rxx) recorded in the parameter space of magnetic field B and carrier density n) of a typical device with square DNA superlattice (Sample-S18) as shown in (b). Here Rxx is the longitudinal resistance. e Landau fan map of a typical device with hexagonal DNA superlattice (Sample-S23). f Control sample of a square DNA/h-BN/graphene/h-BN heterostructure with graphene and h-BN aligned at an angle close to zero degree. Samples in (d) and (e) are intentionally made to avoid alignment of graphene and h-BN during device fabrications. g The Landau Levels (LLs) (black: graphene; red: square DNA superlattice; green: hexagonal DNA superlattice; blue: aligned h-BN/graphene) extracted from (d) and (e) with the filling fractions labeled in each LL. The blue dashed line in (f) and (g) indicates the minimum carrier density for the origin of a Landau fan induced by almost perfectly aligned graphene/h-BN in our control sample, which is much higher than the observed mini-fans in (d) and (e).
