Multi-Scale, Multi-Modal Imaging and Spectroscopy for Quantum Materials and Devices

The next leap in computing technologies and capabilities will emerge from the integration of novel materials families into nano-scale devices. Spintronics, for example, offer the possibility of extremely low-power computation, but require new materials platforms which can be tuned to provide the desired functional properties. Scanning transmission electron microscopy (STEM) and related techniques offer unique and powerful insights for the synthesis of these compounds and their fabrication into atomic-scale devices, when experimental challenges of beam-sensitive materials can be overcome. Here I will discuss how new strategies and advances for signal-limited STEM, including high-brightness electron sources and low-noise detectors, can inform new approaches for stabilizing coexisting magnetic and charge-ordered phases in intercalated van der Waals (vdW) compounds which host spin-bearing ions in the weak-bonding gap between quasi-two-dimensional layers of the host lattice [1]. In addition to traditional bulk synthesis approaches [2], we leverage a combination of high spatial-resolution structural and spectroscopic measurements through STEM imaging and electron energy loss spectroscopy (EELS) to reveal new synthetic pathways via metal precursor patterning and vacuum annealing pristine vdW flakes [3,4]. Spatially resolved valence analysis shows how the metal intercalants are introduced to the host lattice, inspiring new methods for fabricating bespoke heterostructures and devices with exquisitely tailored properties. Furthermore, atomic-scale structural analysis informs theoretical calculations to show how intercalants can be preferentially introduced in certain stacking configurations of the vdW material. Together, the insights provided by this access to the structural and electronic details of these intercalated compounds provide novel roadmaps for the synthesis and fabrication of entirely unique functional device geometries.<br/><br/>[1] Xie, et al. <i>J. Am. </i><i>Chem. Soc.</i> <b><i>144</i></b>, 9525− 9542 (2022).<br/>[2] Goodge, Gonzalez, et al.<i> ACS Nano</i> <b>17</b> (20), 19865–19876 (2023).<br/>[3] Husremović, et al. <i>J. Am. Chem. Soc.</i> <b><i>144</i></b>, 12167−12176 (2022).<br/>[4] Husremović, et al. arXiv:2406.15261 (2024).