Imaging the dynamics of individually adsorbed molecules.
Nat Mater
; 12(3): 223-7, 2013 Mar.
Article
en En
| MEDLINE
| ID: mdl-23263642
ABSTRACT
Although noise is observed in many experiments, it is rarely used as a source of information. However, valuable information can be extracted from noisy signals. The motion of particles on a surface induced, for example, by thermal activation or by the interaction with the tip of a scanning tunnelling microscope may lead to fluctuations or switching of the tunnelling current. The analysis of these processes gives insight into dynamics on a single atomic or molecular level. Unfortunately, scanning tunnelling microscopy (STM) is not a useful tool to study dynamics in detail, as it is an intrinsically slow technique. Here, we show that this problem can be solved by providing a full real-time characterization of random telegraph noise in the current signal. The hopping rate, the noise amplitude and the relative occupation of the involved states are measured as a function of the tunnelling parameters, providing spatially resolved maps. In contrast to standard STM, our technique gives access to transiently populated states revealing an electron-driven hindered rotation between the equilibrium and two metastable positions of an individually adsorbed molecule. The new approach yields a complete characterization of copper phthalocyanine molecules on Cu(111), ranging from dynamical processes on surfaces to the underlying electronic structure on the single-molecule level.
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Bases de datos:
MEDLINE
Idioma:
En
Revista:
Nat Mater
Asunto de la revista:
CIENCIA
/
QUIMICA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Alemania