Phys.org March 1, 2024
Charge density waves are emergent quantum states that spontaneously reduce crystal symmetry, drive metal-insulator transitions, and precede superconductivity. In low-dimensions, distinct quantum states arise, however, thermal fluctuations and external disorder destroy long-range order. A team of researchers in the US (University of Michigan, Harvard University) has stabilized ordered 2D charge density waves through endotaxial synthesis of confined monolayers of 1T-TaS2. Specifically, an ordered incommensurate charge density wave (oIC-CDW) was realized in 2D with dramatically enhanced amplitude and resistivity. By enhancing CDW order, the hexatic nature of charge density waves became observable. Upon heating via in-situ TEM, the CDW continuously melted in a reversible hexatic process wherein topological defects formed in the charge density wave. From these results, new regimes of the CDW phase diagram for 1T-TaS2 were derived and consistent with the predicted emergence of vestigial quantum order… read more. Open Access TECHNICAL ARTICLE
Long-range ordered incommensurate charge density waves. Credit: Nature Communications volume 15, Article number: 1403 (2024)Â