Low-Temperature High Frequency STM System with Vector Magnet Field (6K/7T/200ps)
Our low-temperature STM is located in a three chamber ultra high vacuum system and is working at a temperature of 5K. The cryostat is equipped with two superconducting split coil pairs and a solenoid coil providing a three- dimensional rotatable magnetic field of 500mT. The maximum magnetic field of 7T can be applied perpendicular to the sample surface. The in-plain field maximum is 3T and 0.5T, respectively. The system has a height of 4.7m. In order to reduce vibrations, the whole system is placed into an acoustically insulated room in the basement of the building.
Furthermore, the UHV system is equipped with a LEED/Auger system, various MBE evaporators, ion guns, and a high temperature heating stage (2600K). It is possible to evaporate materials onto the samples at 40 K with the sample within the microscope. Our home-made STM has been designed for the use in high magnetic fields, at low temperatures and at UHV conditions. The probing tip can be exchanged without breaking the vacuum. A sample positioning stage allows a lateral displacement of the sample over a range of 2mm. The microscope is compatible with high-frequency and has a time resolution (pump-probe operation) of 200 ps. Test measurements result in a z-noise of about 120 fm (rms value).