High-resolution scanning tunneling spectroscopy of magnetic impurity induced bound states in the superconducting gap of Pb thin films

Phys Rev Lett. 2008 Jun 6;100(22):226801. doi: 10.1103/PhysRevLett.100.226801. Epub 2008 Jun 5.


Tunneling spectra for individual atoms and dimers of Mn and Cr adsorbed on superconducting Pb thin films were measured by a low temperature scanning tunneling microscope. Multiple-resonance structures within the superconducting gap on the adsorbates were resolved and interpreted as the magnetic impurity-induced bound states associated with different scattering channels. The experiment demonstrates a spectroscopic approach to characterizing the spin states of magnetic structures and exploring the competition between superconductivity and magnetism at the nanometer scale.