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. Here we stabilize ordered two-dimensional (2D) charge density waves through endotaxial synthesis of confined monolayers of 1T-TaS2. Specifically, an ordered incommensurate charge density wave (oIC-CDW) is realized in 2D with dramatically enhanced amplitude and resistivity. By enhancing CDW order, the hexatic nature of charge density waves becomes observable. Upon heating via in-situ TEM, the CDW continuously melts in a reversible hexatic process wherein topological defects form in the charge density wave. From these results, new regimes of the CDW phase diagram for 1T-TaS2 are derived and consistent with the predicted emergence of vestigial quantum order.
@article{arxiv.2307.04587,
title = {Endotaxial Stabilization of 2D Charge Density Waves with Long-range Order},
author = {Suk Hyun Sung and Nishkarsh Agarwal and Ismail El Baggari and Yin Min Goh and Patrick Kezer and Noah Schnitzer and Yu Liu and Wenjian Lu and Yuping Sun and Lena F. Kourkoutis and John T. Heron and Kai Sun and Robert Hovden},
journal= {arXiv preprint arXiv:2307.04587},
year = {2024}
}