Scanning tunneling microscopy and spectroscopy at very low temperatures

• Published in: Journal of physics. Conference series Vol. 568; no. 2; p. 22045
• Main Authors: Guillamon, I, Rodrigo, J G, Vieira, S, Suderow, H
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 08.12.2014
• Subjects: Anisotropy; Charge density waves; Density of states; Dilution; Electronic systems; Elementary excitations; Low temperature; Microscopy; Physics; Scanning tunneling microscopy; Spectrum analysis; Superconductors; Thin films; Vortices
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/568/2/022045

During past decades, an increasing number of laboratories is using cryogenic scanning tunneling microscopy and spectroscopy (STM/S) to probe different kinds of electronic systems. Measurements in a dilution refrigerator are particularly useful to study superconductors, because temperatures of order of 100 mK are well below most critical temperatures and effectively reduce thermally excited quasiparticles. The local electronic density of states is then obtained at atomic level with a resolution in energy of some tens of μeV. Visualizing spatial variations of the local density of states allows characterizing vortex cores and the vortex lattice. Vortex core electronic features provide the anisotropy of the superconducting properties, and help understanding the influence of competing orders such as charge density waves. Here we will review results in dichalcogenide superconductors, in the magnetic borocarbide TmNi2B2C and in thin films, discussing in some detail a few relevant aspects of thermal depinning and melting in thin films.