Atomic-Resolution Cryo-STEM Across Continuously Variable Temperatures

Abstract

Atomic-resolution cryogenic scanning transmission electron microscopy (cryo-STEM) has provided a path to probing the microscopic nature of select low-temperature phases in quantum materials. Expanding cryo-STEM techniques to broadly tunable temperatures will give access to the rich temperature-dependent phase diagrams of these materials. With existing cryo-holders, however, variations in sample temperature significantly disrupt the thermal equilibrium of the system, resulting in large-scale sample drift. The ability to tune the temperature without negative impact on the overall instrument stability is crucial, particularly for high-resolution experiments. Here, we test a new side-entry continuously variable temperature dual-tilt cryo-holder which integrates liquid nitrogen cooling with a 6-pin micro-electromechanical system (MEMS) sample heater to overcome some of these experimental challenges. We measure consistently low drift rates of 0.3–0.4 Å/s and demonstrate atomic-resolution cryo-STEM imaging across a continuously variable temperature range from ~100 K to well above room temperature. We conduct additional drift stability measurements across several commercial sample stages and discuss implications for further developments of ultra-stable, flexible cryo-stages.

Perspective: Challenges and Transformative Opportunities in Superconductor Vortex Physics

“…For insitu TEM to be beneficial to superconductors, samples must be cooled to cryogenic temperatures and studied under the influence of magnetic fields. Developed in the 1960s, liquid helium cooled stages have been used to study superconductors, solidified gases, and magnetic domains 223 , initially without the benefit of aberration-corrected systems with atomic-scale resolution. More recently, cryogenic STEM with atomic scale resolution has been used to study quantum materials, including lowtemperature spin states.…”

Cryogenic Atomic Resolution and 4D STEM Imaging for Energy and Quantum Materials

“…For example, exotic states in quantum materials usually only occur at a low temperature (T); and lithium metal and solid electrolyte interphase layers in battery materials are extremely sensitive to electron irradiation induced heating. The largest challenge in in situ cryo-STEM for materials science currently is the limited stage and temperature stability, making imaging at atomic resolution or at intermediate temperatures difficult [7]. Achieving a sufficient stability is even more challenging for Cryo-4D-STEM, where a longer acquisition is usually needed than for STEM imaging using a conventional detector.…”

Tracking motion of topological defects in a stripe charge-ordered phase with continuously variable temperature cryo-STEM

“…The strong temperature dependence of many strongly correlated phenomena makes cryogenic temperature control key to studying the emergence, interaction, and transitions of these phases [1,2]. Using a recently developed side-entry holder which enables stable STEM imaging at temperatures from ~100-1000 K [3], we have measured the PLDs in a charge ordered manganite from the low temperature commensurate phase to just below T c , near room temperature. The holder's high stability and fast temperature control enable tracking of the same region of interest through complete temperature cycles, allowing the picometer scale displacements of every atomic column in the field of view to be measured at each temperature step.…”