LT-3

The LT-3 is the third low-temperature scanning tunneling microscope (STM) available at EP2.  Similar to LT-2 it was designed and built in-house within a master project.  Although general specifications, such as the operation temperature (5 Kelvin) and the ultra-high vacuum (UHV) system are almost identical (see gallery images below), the design was optimized to reach best possible stability.  For example, the cryostat includes an air-damping system which isolates the helium dewar from mechanical and acoustic vibrations.  Furthermore, the STM head has a conical shape to increase its stiffness and thereby the resonance frequencies.

The LT-3 is mainly used for nanomagnetism studies of metallic systems.  For example, this setup was employed to investigate the exchange splitting of the surface electronic states of nickel Ni(111) by quasiparticle interference (published in Physical Review B).  Furthermore, we investigated the thickness-dependent evolution of the magnetic domain structure of iron (Fe) films on a rhodium substrate.  By using magnetically coated probe tips we performed spin-polarized scanning tunneling microscopy (SP-STM) experiments and successfully imaged the magnetic structure of Fe/Rh(001) with atomic spin resolution.