Multiscale Characterization of Quantum Materials

Quantum materials, defined by their unique electronic properties, are central to current scientific and technological research. Their distinct conductivity and complex phase behaviour present an intriguing puzzle with both opportunities and challenges. Central to this exploration is the interplay between microstructures, compositional changes, and the resulting electronic properties. Adopting a multiscale approach provides essential insights into the impacts of these atomic-scale changes on the material’s functional properties. In this presentation, we utilize the topical superconductor Fe(Se,Te) to showcase the importance of applying advanced multiscale characterization techniques. Initial bulk characterization confirmed the quality of our material system, indicating high-quality homogeneous single crystals. However, local real-space mapping of the enhanced conductivity of the superconducting phase, via low temperature conductive atomic force microscopy (cAFM), revealed unexpected spatial inhomogeneities. Specifically, across five orders of real space imaging, we see that the majority of the crystal is relatively insulating, with only localized regions of heightened conductivity. To confirm and substantiate these observations, we use atom probe tomography (APT) and energy dispersive x-rays (EDX) to discern that the different regions have distinct chemical compositions. This highlights the vital role of multiscale characterization in quantum materials, illustrating their true complexities that may elude classical characterization techniques. Such approaches are essential for refining our methods and advancing quantum material research.