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Local variations in the Seebeck coefficient in low-dimensional materials-based nanostructures and devices play a major role in their thermoelectric performance. Unfortunately, currently most thermoelectric measurements probe the aggregate characteristics of the device as a whole, failing to observe the effects of the local variations and internal structure. Such variations can be caused by local defects, geometry, electrical contacts or interfaces and often substantially influence thermoelectric properties, most profoundly in two-dimensional (2D) materials. Here, we use Scanning Thermal Gate Microscopy (STGM), a non-invasive method not requiring an electrical contact between the nanoscale tip and the probed sample, to obtain nanoscale resolution 2D maps of the thermovoltage in graphene samples. We investigate a junction formed between single-layer and bilayer graphene and identify the impact of internal strain and Fermi level pinning by the contacts using a deconvolution method to directly map the local Seebeck coefficient. The new approach paves the way for an in-depth understanding of thermoelectric behaviour and phenomena in 2D materials nanostructures and devices.
This paper presents an overview of scanning-gate microscopy applied to the imaging of electron transport through buried semiconductor nanostructures. After a brief description of the technique and of its possible artifacts, we give a summary of some
In this work we present the results of an experiment to locally resolve the spin Seebeck effect in a high-quality Pt/YIG sample. We achieve this by employing a locally heated scanning thermal probe to generate a highly local non-equilibrium spin curr
We study the relationship between the local density of states (LDOS) and the conductance variation $Delta G$ in scanning-gate-microscopy experiments on mesoscopic structures as a charged tip scans above the sample surface. We present an analytical mo
In scanning gate microscopy, where the tip of a scanning force microscope is used as a movable gate to study electronic transport in nanostructures, the shape and magnitude of the tip-induced potential are important for the resolution and interpretat
In the current paper a set of experiments dedicated to investigations of local electronic transport in undoped InAs nanowires at helium temperatures in the presence of a charged atomic-force microscope tip is presented. Both nanowires without defects