View article

The design of new materials with increasingly smaller structural features and with new properties requires detailed understanding of the structure, bonding nature between atoms and new tools to probe the electronic structure features. Modern transmission electron microscopes provide unprecedented spatial and energy resolution so that local measurements with electron energy loss spectroscopy (EELS) can be related to physical properties such as the optical response or transport. For the study of thin films of complex oxides few monolayers thick and for nanowires (either metallic or wide bandgap), transmission electron microscopy and EELS becomes therefore the tools of choice for providing both the high spatial resolution and high energy resolution necessary to probe the local structure, bonding and electronic structure of these materials. Our work is carried out with an ultrahigh-resolution S/TEM (FEI Titan 80-3003) equipped with two aberration correctors and a monochromator with a high-brightness electron source. To demonstrate the very high energy resolution achieved in this system, we will demonstrate the detection of low energy-loss features in plasmonic nanostructures down to the infrared part of the electron energy loss spectrum by directly imaging resonances at 0.5 eV [1] and even down to 0.2 eV, the lowest features currently detected with electron energy loss spectroscopy. We have used this capability to study how these very low energy features provide information about nanowires structures and confirm theoretical prediction about plasmon resonance behaviour in low dimensions. Using the atomic resolved capabilities of our …