Taking Low Energy Excitations at High Spatial Resolution to Low Temperatures

Over the last decade, modern monochromated electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) has achieved the ability to combine ultrahigh energy and spatial resolution simultaneously. As a result, a new wave of experiments on ultralow energy excitations, such as phonons, phonon-polaritons, molecular vibrations, shallow electronic structure, and infrared optical excitations have achieved exciting results in the STEM.<br/><br/>The emergence of monochromators that can reach the mid-infrared has largely coincided with the development of stable cryogenic TEM holders that can reach ultralow temperatures. However, due to the relative recency of both techniques achieving consistency and accessibility only limited opportunities have been available to combine them on the same materials systems. Here, I will show recent work at ORNL on the combining cryo-STEM and monochromated EELS. Focusing on cryogenic phase changes, emergent behavior at cryo-temperatures, and the effect of low-temperatures on beam-sensitive materials.<br/><br/><i>This abstract has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).</i>