Theoretical assessment of Raman spectra on MXene Ti2C: from monolayer to bilayer.
Theoretical assessment of Raman spectra on MXene Ti2C: from monolayer to bilayer.
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DOI：
10.1039/d1cp03117a
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发表时间：
2021-09
期刊：
影响因子：
--
通讯作者：
Haiming Huang;Weiliang Wang;Shaolin Zhang
中科院分区：
文献类型：
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作者：
Haiming Huang;Weiliang Wang;Shaolin Zhang
采用第一性原理计算方法，研究了两种常用激光（532 nm和633 nm）激发下单层和双层Ti2C的结构、振动和拉曼光谱特性，建立了二维MXene的层结构和光学特性之间的关联.的单分子层的稳定性和积极优选的堆叠配置的声子色散证明。发现单层和双层Ti2C系统表现出不同的点群对称性，从而由于层间货车德瓦尔斯相互作用引起的双层结构的对称性破缺而表现出不同的拉曼特性。我们列出了单层（双层）Ti2C的所有拉曼活性模式，即，一（五）个面外A1g（A1）和一（五）对简并面内Eg（E）振动模式。根据平行（垂直）结构中两个（四个）最大值的位置讨论了偏振角相关的拉曼强度，这可能适用于实验识别单层和双层Ti 2 C。单层和双层Ti2C的偏振方向平均拉曼光谱的差异可以用光吸收特性来解释。
The structural, vibrational and Raman spectra properties of monolayer and bilayer Ti2C excited by two commonly used laser lines (532 nm and 633 nm) are investigated by first principles calculations to establish a correlation among layer stacks and optical features for two-dimensional MXenes. The stability of the monolayer and the energetically preferable stacking configuration are demonstrated by phonon dispersion. The monolayer and bilayer Ti2C systems are found to exhibit different point group symmetries and thereby the Raman properties due to the symmetry breaking of the bilayer structure caused by interlayer van der Waals interactions. We listed all Raman-active modes for monolayer (bilayer) Ti2C, i.e., one (five) out-of-plane A1g (A1) and one (five) pair (pairs) of degenerate in-plane Eg (E) vibration modes. Polarization angle dependent Raman intensity has been discussed in terms of the locations of two (four) maxima in the parallel (perpendicular) configuration, which might be applied in experimentally identifying monolayer and bilayer Ti2C. The difference in the polarization direction averaged Raman spectra between monolayer and bilayer Ti2C can be explained by the characteristics of light absorbance.