VACUUM-TUNNELING SPECTROSCOPY ON HEAVY-FERMION COMPOUNDS USING A LOW-TEMPERATURE TUNNELING MICROSCOPE

Vacuum-tunnelling spectroscopy on superconducting heavy-fermion compou nds should be a suitable method to gain information on the superconduc ting order parameter. We constructed a scanning-tunnelling microscope for the use in a dilution refrigerator. Its miniaturised design provid es good thermal coupling of the sample and excellent mechanical stabil ity, yielding atomic resolution. We present topographic and spectrosco pic results on graphite (HOPG), as well as on classical and heavy-ferm ion superconductors.