Nuclear and electronic resonance spectroscopy of single molecules by radio-frequency scanning tunnelling microscopy

摘要

The ongoing miniaturization in nanoscience and -technology challenges thesensitivity and selectivity of experimental analysis methods to the ultimatelevel of single atoms and molecules. A promising new approach, addressed here,focuses on the combination of two well-established complementary techniquesthat have proven to be very successful in their own fields: (i) low-temperaturescanning tunneling microscopy (STM), offering high spatial resolution forimaging and spectroscopy together with the capability of manipulating singleatoms and molecules in a well-controlled manner; (ii) radio-frequency (rf)magnetic resonance techniques, providing paramount analytical power based on ahigh energy resolution combined with the versatility of being sensitive to agreat variety of different properties of matter. Here, we demonstrate thesuccessful resonant excitation and detection of nuclear and electronic magnetictransitions of a single quantum spin in a single molecule by rf tunneling ofelectrons applied through the tip of a modified STM instrument operated at 5 K.The presented rf-STM approach allows the unrivalled spectroscopic investigationof electronic hyperfine levels in single molecules with simultaneoussub-molecular spatial resolution. The achieved single-spin sensitivityrepresents a ten orders of magnitude improvement compared to existing methodsof magnetic resonance - offering, atom-by-atom, unprecedented analytical powerand spin control with impact to physics, chemistry, biology, medicine,nanoscience and -technology.