DESIGN PRINCIPLES OF A VARIABLE-TEMPERATURE SCANNING TUNNELING MICROSCOPE

We report on the construction of a variable temperature scanning tunneling microscope (STM) operating from 20 to 700 K in UHV, which routinely allows one to image dense packed metal surfaces in atomic resolution down to the lowest temperature. Central problems in designing a variable temperature STM are discussed in some detail. Methods to achieve efficient vibration isolation between the cryostat and the STM are presented. Furthermore, a sample and sample holder assembly is described, which ensures long-term mechanical stability and STM imaging, while subject to extreme temperature variations. The temperature response of the STM while cooling and heating the sample is measured and will be discussed. (C) 1995 American Institute of Physics.