@article{c822c1479c364e36b1da8d595a2fff5e,
title = "Distinct surface and bulk charge density waves in ultrathin 1T-Ta S2",
abstract = "We employ low-frequency Raman spectroscopy to study the nearly commensurate (NC) to commensurate (C) charge density wave (CDW) transition in 1T-TaS2 ultrathin flakes protected from oxidation. We identify additional modes originating from C-phase CDW phonons that are distinct from those seen in bulk 1T-TaS2. We attribute these to CDW modes from the surface layers. By monitoring individual modes with temperature, we find that surfaces undergo a separate, low-hysteresis NC-C phase transition that is decoupled from the transition in the bulk layers. This indicates the activation of a secondary phase nucleation process in the limit of weak interlayer interaction, which can be understood from energy considerations.",
author = "Rui He and Zhipeng Ye and Gaihua Ye and Heidi Anderson and Xia Dai and Xianxin Wu and Jiangping Hu and Yu Liu and Wenjian Lu and Yuping Sun and Pasupathy, {Abhay N.} and Tsen, {Adam W.}",
note = "Funding Information: The low-temperature equipment was acquired through the NSF MRI Grant (No. DMR-1337207). Work at Columbia University is supported by the NSF via Grants No. 1124894 (A.W.T.) and No. DMR-1056527 (A.N.P.). Work in China was supported by the National Key Research and Development Program (2016YFA0300404), the National Nature Science Foundation of China (11674326, 11404342), the Joint Funds of the National Natural Science Foundation of China, and the Chinese Academy of Sciences Large-scale Scientific Facility (U1232139). Publisher Copyright: {\textcopyright} 2016 American Physical Society.",
year = "2016",
month = jan,
day = "1",
doi = "10.1103/PhysRevB.94.201108",
language = "English",
volume = "94",
journal = "Physical Review B",
issn = "2469-9950",
number = "20",
}