| Autor: |
Wen, Muqian, Chen, Xuexian, Zheng, Zebo, Deng, Shaozhi, Li, Zhibing, Wang, Weiliang, Chen, Huanjun |
| Zdroj: |
The Journal of Physical Chemistry - Part C; January 2021, Vol. 125 Issue: 1 p765-773, 9p |
| Abstrakt: |
Van der Waals (vdW) α-MoO3has a strong anisotropic phonon polariton effect in the middle- and far-infrared up to terahertz band. This can be of a great importance for developing new nanophotonics and optoelectronic devices. The anisotropic phonon polaritons originate from the anisotropic lattice vibrational properties. Therefore, the phonon modes of α-MoO3, especially the in-plane anisotropic phonon modes, should be systematically studied. To the best of our knowledge, there are no correlative theoretical and experimental studies on the phonon behaviors in vdW α-MoO3thin films (∼100 nm). Here, the lattice vibrational properties of α-MoO3were investigated using density functional theory and polarization-resolved Raman spectroscopy. Several Ag modes, whose polarization-resolved Raman spectra could be used for identifying the orientation of the α-MoO3crystal, were observed. Furthermore, it was demonstrated that modes with higher frequency have longer lifetimes, and the phonon modes in bulk α-MoO3have longer lifetimes than those in monolayer α-MoO3. The group velocity of each mode was also obtained. These results can help understand the physical origin of the highly anisotropic phonon polaritons in α-MoO3and other types of vdW crystals. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
