Development of a new ULT scanning tunneling microscope at University of Tokyo

We describe design concepts and some technical details of a new ultra-low temperature scanning tunneling microscope (ULT-STM) which is now under construction at University of Tokyo. It is designed to work with an atomic resolution at temperatures down to 20 mK and in magnetic fields up to 6 T. It is possible to change samples and STM tips keeping ultra high vacuum and low temperature environments, which allows us to study almost all conducting materials and adsorbed samples.