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Birefringence‐Directed Raman Selection Rules in 2D Black Phosphorus Crystals
Author(s) -
Mao Nannan,
Wu Juanxia,
Han Bowen,
Lin Jingjing,
Tong Lianming,
Zhang Jin
Publication year - 2016
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201600295
Subject(s) - birefringence , raman spectroscopy , anisotropy , materials science , raman scattering , optics , crystal (programming language) , depolarization ratio , nanoscopic scale , molecular physics , condensed matter physics , chemistry , nanotechnology , physics , computer science , programming language
The incident and scattered light engaged in the Raman scattering process of low symmetry crystals always suffer from the birefringence‐induced depolarization. Therefore, for anisotropic crystals, the classical Raman selection rules should be corrected by taking the birefringence effect into consideration. The appearance of the 2D anisotropic materials provides an excellent platform to explore the birefringence‐directed Raman selection rules, due to its controllable thickness at the nanoscale that greatly simplifies the situation comparing with bulk materials. Herein, a theoretical and experimental investigation on the birefringence‐directed Raman selection rules in the anisotropic black phosphorus (BP) crystals is presented. The abnormal angle‐dependent polarized Raman scattering of the A g modes in thin BP crystal, which deviates from the normal Raman selection rules, is successfully interpreted by the theoretical model based on birefringence. It is further confirmed by the examination of different Raman modes using different laser lines and BP samples of different thicknesses.