The Exchange Interaction between Localized and Itinerant Electrons in TmTe and GdTe Films

We propose to probe the d-f exchange interaction by measuring the response of the itinerant states to an external magnetic field. Two rare-earth monotellurides, TmTe and GdTe, are chosen to demonstrate the mechanism. The thin films of both compounds were prepared by molecular beam epitaxy and studied by scanning tunneling microscopy and spectroscopy. For the TmTe film, the spin degree of freedom of the d-electron exhibits a large response to the magnetic field. For the GdTe film, the magnetic field induces a metal-insulator transition.