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تسجيل مستخدم جديدScanning gate microscopy of current-annealed single layer graphene
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We have used scanning gate microscopy to explore the local conductivity of a current-annealed graphene flake. A map of the local neutrality point (NP) after annealing at low current density exhibits micron-sized inhomogeneities. Broadening of the local e-h transition is also correlated with the inhomogeneity of the NP. Annealing at higher current density reduces the NP inhomogeneity, but we still observe some asymmetry in the e-h conduction. We attribute this to a hole doped domain close to one of the metal contacts combined with underlying striations in the local NP.
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We use Scanning Gate Microscopy to demonstrate the presence of localized states arising from potential inhomogeneities in a 50nm-wide, gate-defined conducting channel in encapsulated bilayer graphene. When imaging the channel conductance under the in
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We use scanning gate microscopy to map out the trajectories of ballistic carriers in high-mobility graphene encapsulated by hexagonal boron nitride and subject to a weak magnetic field. We employ a magnetic focusing geometry to image carriers that em
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We use low-temperature scanning gate microscopy (SGM) to investigate the breakdown of the quantum Hall regime in an exfoliated bilayer graphene flake. SGM images captured during breakdown exhibit intricate patterns of hotspots where the conductance i
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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
of its most instructive achievements found in the literature and we present an updated review of our own research. It focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. In all of the given examples, we emphasize how a local-probe approach is able to shed new, or complementary, light on transport phenomena which are usually studied by means of macroscopic conductance measurements.
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
ion of the measurements. Contaminations picked up during topography scans may significantly alter this potential. We present an in situ high-field treatment of the tip that improves the tip-induced potential. A quantum dot was used to measure the tip-induced potential.
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