SPICE Workshop on Unconventional Superconductors and Magnets May 12th - 14th, 2026
Philip Kim
Quasicrystals (QCs) exhibit deterministic atomic-scale structures with disallowed orientational crystal symmetry. The long-range orientational order in QCs, without translational periodicity, may offer a distinct yet complementary approach to exploring correlated states. Van der Waals (vdW) atomic layers result in weak interactions between atomic layers, forming two-dimensional (2D) atomic structures through mechanical exfoliation. In this presentation, I will discuss the structures and electronic properties of the van der Waals QC Ta₁.₆Te. Using atomic-resolution transmission electron microscopy, we characterized the atomic structure of the Ta₁.₆Te QC using square–triangle tiling. Direct structural imaging allowed us to resolve the fundamental tile patterns and analyze the interplay between QC and AC phases in terms of their distinct symmetry properties. Using higher-dimensional embedding methods, we have established a unified phason-based description that captures the essential differences between the QC and AC phases. Furthermore, diffraction studies allow us to quantify phason strain fields and extract phason stiffness, highlighting the elastic nature of quasiperiodic fluctuations. Remarkably, TaTe also exhibits unconventional electronic transport and superconductivity whose characteristics appear intimately tied to its quasicrystalline order and phason dynamics. By contrasting quasicrystalline order with moiré periodicity, our results expand the landscape of van der Waals (vdW) materials and point to new areas in which structural aperiodicity governs correlated electronic phenomena.