Fig. 1: SThEM on a TBG sample.
From: Thermal biasing for lattice symmetry breaking and topological edge state imaging
A Experimental Setup of our UHV-SThEM, modified by the contact-mode AFM system (Scienta Omicron VT-SPM). The tip and sample are thermally decoupled in the system. The temperature gradient between the tip (Ttip) and sample (Tsample) induces thermoelectric voltages. The in-plane transport of the sample can be measured by the separately connected SMU (source-measure unit). B The measured thermoelectric voltage (ΔV)-temperature gradient (ΔT = Tsample-Ttip) curve of a TBG region with a twist angle of 1.1° above room temperature. The tip was maintained as Ttip = 300 K while the sample was heated. The positive slope yields a thermopower (Seebeck coefficient) of +8.94 μV/K, indicating slight p-type doping of the intrinsic TBG on a h-BN. C Schematic image for the possible stacking orders of TBG with a small twist angle. D Thermopower mapping image of TBG with an averaged twisted angle of 1.1° with a ∆T = 20 K. E, F Thermopower mapping images of TBG with a twisted angle of 0.3° and 0.07°, respectively. The different twist angles were obtained at different regions in a single TBG sample.
