Reversible Manipulations of Triangular-Shaped Mirror Twin Boundary Loops in Ultrathin NiTe<sub>2</sub>.

Cheng, Yujin; Wu, Xinyan; Ding, Haoxuan; Quan, Wenzhi; Zhou, Tong; Wang, Jialong; Peng, You; Wang, Xiyao et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

High-density mirror twin boundaries (MTBs) embedded in two-dimensional (2D) transition metal dichalcogenides (TMDCs) have emerged as fascinating platforms for exploring charge density wave and Tomonaga-Luttinger liquid-related issues. However, the reversible manipulation of high-density MTBs in 2D TMDCs remains challenging. Herein, we report the first fabrication of high-density MTB loops in ultrathin 1T-NiTe<sub>2</sub> on the SrTiO<sub>3</sub>(001) substrate, by postannealing as-grown 1T-NiTe<sub>2</sub> under Te-deficient conditions. This formation process is found to be mediated by the generation, accumulation, and assembly of Te vacancies into triangular vacancy loops in ultrathin 1T-NiTe<sub>2</sub>, according to on-site scanning tunneling microscopy/spectroscopy (STM/STS) characterizations combined with density functional theory (DFT) calculations. Unique charge density modification is also observed to be correlated with the length of the one-dimensional MTBs. Overall, this work should inspire further investigations of the formation mechanism and exotic physical properties of one-dimensional electron systems in ultrathin TMDCs.