Wang Yongsong, Chen Fengming, Guo Xiao, Liu Jinxin, Jiang Junjie, Zheng Xiaoming, Wang Zihan, Al-Makeen Mansour M, Ouyang Fangping, Xia Qinglin, Huang Han
School of Physics and Electronics, Hunan Key Laboratory of Nanophotonics and Devices, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, P. R. China.
School of Physics and Electronics, Hunan Key Laboratory of Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, P. R. China.
J Phys Chem Lett. 2021 Nov 11;12(44):10753-10760. doi: 10.1021/acs.jpclett.1c03218. Epub 2021 Oct 29.
Group-VA two-dimensional layered materials in a puckered honeycomb structure exhibit strong in-plane anisotropy and have emerged as new platforms for novel devices. Here, we report on systematic Raman investigations on exfoliated b-As flakes on the A and A polarization dependence on their symmetry, excitation wavelength, and flake thickness. The intensity maximums of both phonons are corrected in the b-As armchair direction under 633 nm excitation regardless of the flake thickness upon considering optical birefringence effects and interference effects. The intensity ratio of A to A modes under 532 nm excitation is useful for b-As crystalline orientation identification. Temperature-dependent Raman investigations reveal the linearly anharmonic behaviors of both phonons in the range from 173 to 293 K and a slightly greater first-order temperature coefficient in the zigzag direction. Our findings give deep insight into the in-plane phonon anisotropy and anharmonicity of b-As and provide a step toward future device applications.
具有褶皱蜂窝结构的VA族二维层状材料表现出很强的面内各向异性，并已成为新型器件的新平台。在此，我们报告了对剥落的b-As薄片在A和A偏振下，其对称性、激发波长和薄片厚度的系统拉曼研究。在考虑光学双折射效应和干涉效应的情况下，无论薄片厚度如何，在633 nm激发下，两种声子的强度最大值都在b-As扶手椅方向得到校正。532 nm激发下A与A模式的强度比可用于b-As晶体取向识别。温度相关的拉曼研究揭示了两种声子在173至293 K范围内的线性非谐行为，以及在锯齿方向上稍大的一阶温度系数。我们的发现深入了解了b-As的面内声子各向异性和非谐性，并为未来的器件应用迈出了一步。
