Raman Spectroscopy of Two-Dimensional Borophene Sheets.

Sheng, Shaoxiang; Wu, Jiang-Bin; Cong, Xin; Zhong, Qing; Li, Wenbin; Hu, Wenqi; Gou, Jian; Cheng, Peng et al. · ACS Nano · 2019

basic_science · Level V

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Abstract

The successful fabrication of a two-dimensional boron sheet, which features a triangular lattice with periodic hole arrays, has stimulated great interest in its specific structure as well as properties such as possible superconductivity. Here, we report a study on the vibrational spectra and electron-phonon coupling (EPC) in monolayer boron sheets by in situ Raman and tip-enhanced Raman spectroscopy (TERS) at low temperature and ultrahigh vacuum. The gap-mode TERS gives a 3 × 10<sup>9</sup> selective enhancement on vertical vibrational Raman modes. A spatial resolution of 1 nm is achieved in this system. Combined with first-principle calculations, the vibrational properties as well as EPC in borophene are determined. The results are helpful for further study on the mechanical, electronic, and possible superconducting properties of two-dimensional boron.