We simultaneously measured the distance dependence of the force and the tunnelling current between a W(111) tip and a Au(111) sample in an ultrahigh vacuum at T = 150 K. The tip was characterized by field ion microscopy. Even at atomically close contact no evidence of structural instabilities was found. The scaling of the force curves show an unexpectedly long distance scaling parameter of λ = ...

Hydrogen bonding has a ubiquitous role in electron transport and in molecular recognition, with DNA base pairing being the best-known example. Scanning tunnelling microscope images and measurements of the decay of tunnel current as a molecular junction is pulled apart by the scanning tunnelling microscope tip are sensitive to hydrogen-bonded interactions. Here, we show that these tunnel-decay s...

highly self-ordered alumina nanopore arrays were fabricated using hard anodization technique in different mixtures of oxalic/phosphoric acid. the phosphoric acid concentration was varied from 0.05 to 0.3 m while the oxalic acid concentration was changed between 0.3 and 0.4 m. the self ordered nanoporous arrays were obtained in anodization voltage changing from 130 to 200 v. the interpore distan...

– the normal and lateral line cycloid scales of a cyprinid fish capoeta damascina (valenciennes incuvier and valenciennes, 1842) have been subjected to the scanning electron microscopy technique in orderto study their detailed structure. the scales have the general morphological characteristics of the cycloidscales. in the normal scale located below the dorsal fin, the focus lies towards the an...

The room temperature growth and ordering of (porphyrinato)nickel(II) (nickel(II) porphine, NiP) molecules on the Ag/Si(111)-(√3 × √3)R30o surface have been investigated using scanning tunnelling microscopy/spectroscopy (STM/STS) and low-energy electron diffraction (LEED). Results indicate a well-ordered molecular layer in which the porphyrin molecules have a flat orientation with the molecular ...

The unique crystalline protection of the surface states in topological crystalline insulators has led to a series of predictions of strain-generated phenomena, from the appearance of pseudo-magnetic fields and helical flat bands to the tunability of Dirac surface states by strain that may be used to construct 'straintronic' nanoswitches. However, the practical realization of this exotic phenome...

Theory predicts that the application of an electric field breaks inversion symmetry AB and BA stacked domains in twisted bilayer graphene, resulting formation a triangular network one-dimensional valley-protected helical states. This two-dimensional states has been observed several studies, but direct experimental evidence electronic transport these is still lacking. In this study, we report ex...