1. Slow, Nanometer Light Confinement Observed in Atomically Thin TaS2
- Author
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Do, Hue T. B., Zhao, Meng, Li, Pengfei, Soh, Yu Wei, Rangaraj, Jagadesh, Liu, Bingyan, Jiang, Tianyu, Zhang, Xinyue, Lu, Jiong, Song, Peng, Teng, Jinghua, and Bosman, Michel
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Extreme light confinement down to the atomic scale has been theoretically predicted for ultrathin, Ta-based transition metal dichalcogenides (TMDs). In this work, we demonstrate in free-hanging 2H-TaS2 monolayers and bilayers slow light behaviour with a group velocity ~ $10^{-4}c$ and a lateral confinement ratio up to 300 at large wave vectors of $q = 0.15 \, \text{{\r{A}}}^{-1}$. Quantitative momentum-resolved electron energy loss spectroscopy (EELS) with an unprecedented momentum resolution of $0.0036 \, \text{{\r{A}}}^{-1}$ was used as a nanoscale optical platform. With it, momentum-dispersed, two-dimensional (2D) plasmon resonances were experimentally observed, showing a transition from 2D to 3D Coulomb interaction in the high-momentum regime, equivalent to light confinement volumes of $1\text{-}2 \, \text{nm}^3$. Remarkably, the resonant modes do not enter the electron-hole continuum, predicting even more enhanced optical field confinements for this material at cryogenic temperatures., Comment: Main Text and Supplemenary Information
- Published
- 2024