Scanning Tunneling Microscopy: Principle and Instrumentation

Scanning tunneling microscopy (STM) has been proven to be an extremely powerful tool for studying the electronic structures of solid-state systems. The STM topographic images, assisted by other surface analysis techniques with chemical specifity, lead to the structural determination of clean and adsorbate-covered surfaces. For example, the first atomically resolved STM image in history confirmed the Si(111) 7 × 7 surface reconstruction [128] and identified Takayanagi's dimer-adatom-stacking-fault model [129] as the correct Si(111) 7 × 7 surface structure. Combining scanning tun-neling microscopy with spectroscopy, a number of beautiful experiments were carried out, e.g., to visualize the standing wave pattern of the two-dimensional surface state electrons in an artificial quantum corral [130, 131], to provide the first direct spectroscopic signature of the Kondo resonance of an isolated magnetic impurity in a non-magnetic host [132], and to map out the electronic density of states inside a single vortex core of the Abrikosov flux lattice for a conventional type II supercon-ductor [133, 134]. Furthermore, spatially resolved tunneling spectroscopy gave invaluable insights into open questions in the physics of strongly correlated electronic systems, such as the correlation between charge ordering and the metal-insulator transition in magnetic manganites [135] and the various ordering phases in high-temperature cuprate superconductors. In this chapter, we summarize the operating principles of scanning tunneling microscopy/spectroscopy and then present our development of a magnetic-field-compatible, cryogenic, variable-temperature STM for the study of cuprate superconductors.