ISSN - 19327447, Journal of Physical Chemistry C, 2016, vol. 120, 25, p. 13843-13849
Energetic and Spatial Mapping of Resonant Electronic Excitations
© 2016 American Chemical Society.In this article, we present a detailed study of the rotational movement of transition metal phthalocyanine molecules ((TM)Pc) on topological insulators by means of scanning tunneling microscopy and spectroscopy. Our data taken on two different systems, namely FePc on Bi2Te3 and MnPc on Sb2Te3, reveal that the energetic onset of the rotational motion coincides with the energetic position of the lowest unoccupied molecular orbital (LUMO). The strong correlation between molecular motion and tunneling into molecular orbitals is corroborated by a very good agreement between the spatial distribution of the switching frequency and the differential conductance map of the LUMO. These results lead to the conclusion that the driving mechanism of the rotational motion is resonant electronic excitation, which we were able to resolve energetically and spatially.