APPLICATIONS WITH A NEW LOW-TEMPERATURE UHV STM AT 5 K

A new dedicated UHV STM for investigations at T less than or equal to 5 K is presented. To achieve such low temperatures and to ensure a hig h thermal stability, the low-temperature (LT) STM described here has a concentric system of bath cryostats. There are openings for tip and s ample exchange at low T, and windows with an infrared radiation shield for optical access, which can both be closed by a door mechanism for LT-STM measurements. Efficient vibration isolation is realized by usin g spring suspension with eddy current damping. With the 3-d coarse pos itioning unit any region of interest within 5 mm by 5 mm on the sample is accessible even at 5 K. For short turn-around cycles the sample an d tip can both be exchanged at low temperatures. Atomically resolved i mages of Au(111) at 5 K in UHV demonstrate the excellent performance o f this LT STM. As a typical application example the appearance of a ch arge-density wave on NbSe2, which occurs below a transition temperatur e of 33.5 K, was imaged.