Figure 1: Hybrid SLG/2DEG devices and the Coulomb drag transport set-up.
From: Anomalous low-temperature Coulomb drag in graphene-GaAs heterostructures
(a,b) Configurations for the Coulomb drag measurements. In a, a voltage drop Vdrag appears in graphene, in response to a drive current Idrive flowing in the 2DEG. In b, the opposite occurs. The drag voltage is measured with a low-noise voltage amplifier coupled to a voltmeter as a function of the applied bias. The drive current is also monitored. (c) Conical massless Dirac fermion band structure of low-energy carriers in SLG. The SLG in this work is hole-doped. (d) Parabolic band structure of ordinary Schrödinger electrons in the 2DEG. (e) Optical micrograph of the device before the deposition of Ohmic contacts. The SLG flake becomes visible in green light after the sample is coated with a polymer (PMMA)31. The scale bar is 10 μm long. (f) Optical microscopy image of the contacted SLG on the etched 2DEG GaAs channel. The red dashed line denotes the SLG boundaries. The scale bar is 10 μm long.
