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 i...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.展开更多
This paper reported the effect of the weak damage in the Al0.25Ga0.75As/GaAs epitaxial layer induced by 0.8 MeV Si ions implantation with ion dose from 1×1014 to 5×1015 cm-2. The Raman spectra measured on th...This paper reported the effect of the weak damage in the Al0.25Ga0.75As/GaAs epitaxial layer induced by 0.8 MeV Si ions implantation with ion dose from 1×1014 to 5×1015 cm-2. The Raman spectra measured on these samples showed that there were two kinds of phonon modes existing in the epitaxial Al0.25Ga0.75As films. The strains induced in the implanted layer and the corresponding lattice parameters were also evaluated as a function of the implanted dose. In addition, the Rutherford backscattering spectrometry/channeling (RBS/C) was also measured on these samples. These two measurement techniques all confirmed that the implantation only induced weak damage in the material.展开更多
Both bi-harmonic maps and f-harmonic maps have some nice physical motivation and applications.Motivated largely by f-tension field not involving Riemannian curvature tensor, we attempt to formalize some large objects ...Both bi-harmonic maps and f-harmonic maps have some nice physical motivation and applications.Motivated largely by f-tension field not involving Riemannian curvature tensor, we attempt to formalize some large objects so as to broaden the notions of f-tension field and bi-tension field. We introduce a very large generalization of harmonic maps called f-bi-harmonic maps as the critical points of f-bi-energy functional, and then derive the Euler-Lagrange equation of f-bi-energy functional given by the vanishing of f-bi-tension field.Subsequently, we study some properties of f-bi-harmonic maps between the same dimensional manifolds and give a non-trivial example. Furthermore, we also study the basic properties of f-bi-harmonic maps on a warped product manifold so that we could find some interesting and complicated examples.展开更多
基金National Natural Science Foundation of China(NSFC)(61604178,61427901,91333207,U1505252)
文摘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the National Natural Science Foundation of China (Grant No. 19975030) .
文摘This paper reported the effect of the weak damage in the Al0.25Ga0.75As/GaAs epitaxial layer induced by 0.8 MeV Si ions implantation with ion dose from 1×1014 to 5×1015 cm-2. The Raman spectra measured on these samples showed that there were two kinds of phonon modes existing in the epitaxial Al0.25Ga0.75As films. The strains induced in the implanted layer and the corresponding lattice parameters were also evaluated as a function of the implanted dose. In addition, the Rutherford backscattering spectrometry/channeling (RBS/C) was also measured on these samples. These two measurement techniques all confirmed that the implantation only induced weak damage in the material.
基金supported by the Science and Technology Research Project of Guangxi Universities(Grant No.2015ZD038)the Key Scientific Research Project of Guangxi University for Nationalities(Grant No.2012MDZD033)
文摘Both bi-harmonic maps and f-harmonic maps have some nice physical motivation and applications.Motivated largely by f-tension field not involving Riemannian curvature tensor, we attempt to formalize some large objects so as to broaden the notions of f-tension field and bi-tension field. We introduce a very large generalization of harmonic maps called f-bi-harmonic maps as the critical points of f-bi-energy functional, and then derive the Euler-Lagrange equation of f-bi-energy functional given by the vanishing of f-bi-tension field.Subsequently, we study some properties of f-bi-harmonic maps between the same dimensional manifolds and give a non-trivial example. Furthermore, we also study the basic properties of f-bi-harmonic maps on a warped product manifold so that we could find some interesting and complicated examples.
