Atomic-resolution transmission electron microscopy techniques hold immense promise for advancing quantum materials research. However, progress has been hindered by the lack of low- temperature capabilities, a prerequisite for studying quantum systems. In this talk, I will highlight two efforts to enable novel cryogenic measurements including the use of liquid helium. The first centers on the development of atomic-resolution cryogenic scanning transmission electron microscopy at liquid nitrogen temperature. This breakthrough development has enabled the imaging of electronic phase transitions and their evolution with picometer precision. I will discuss recent results on charge order transitions and glassy polar order in oxides. Second, I will describe the approach undertaken by our lab in the design and construction of stable liquid helium stages. Liquid helium cooling in the TEM has long posed a formidable challenge, but, if realized, is poised to open new lines of inquiry into a variety of new materials and systems. We show that our liquid helium flow designs provide access to temperatures below 30 K while maintaining atomic resolution performance with sub-Angstrom information transfer. The instrument further enables extended operation durations over 12 hours, low drift (better than 0.4 Å/s), and temperature stability in the millikelvin range at base and intermediate temperatures. Other hardware advances will be discussed, including in situ capabilities. These advances pave the way for novel explorations of ultra-low temperature phenomena in quantum electronic materials.
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