Our main research interests lie in developing detailed physical and chemical understandings of nanoscale materials by means of Scanning Tunneling Microscopy (STM) and Scanning Probe Microscopy (SPM). In addition to the intrinsic properties of materials itself, we are interested in the local variations of electronic properties arising from the external perturbations. Since invention of STM in 1981, the STM studies have enabled us to observe and manipulate single atoms and molecules as well as to understand fundamental quantum phenomena. We are aiming to develop useful insights for basic questions regarding the nature of nanostructures and their interfaces, and ultimately pursue novel nanoscale devices and sensors having better performance.