Elucidation of “phase difference” in Raman tensor formalism
The so-called “phase difference” is commonly introduced as a phenomenological parameter in Raman tensor theory, so as to fit the experimental data well. Although phase difference is widely recognized as an intrinsic property of crystals, its physics still remains ambiguous. Recently, Kranert et al. have presented a new formalism to explain the origin of phase difference theoretically. Here, we systematically conducted experimental research with polar phonons in wurtzite crystals, the results of which strongly suggest that the phase difference should be predetermined in a Raman tensor, rather than be treated as Raman tensor elements traditionally or as an intrinsic property. On the grounds of pinpointing existing logical flaws in Raman tensor study, we provide a logically clear paradigm.
基金项目：National Natural Science Foundation of China (NSFC)10.13039/501100001809 (61604178, 61427901, 91333207, U1505252).
Jingshen Yan：State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-sen University, Guangzhou 510275, China
Fadi Li：Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
Feng Huang：State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-sen University, Guangzhou 510275, China
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Wei Zheng, Jingshen Yan, Fadi Li, and Feng Huang, "Elucidation of “phase difference” in Raman tensor formalism," Photonics Research 6(7), 709-712 (2018)