Optical properties of boron nitride nanotubes
Optical properties of boron nitride nanotubes
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DOI：
10.1143/jpsj.71.2286
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发表时间：
2002-09-01
影响因子：
1.7
通讯作者：
Lin, MF
中科院分区：
文献类型：
--
作者：
Chen, RB;Shyu, FL;Lin, MF
对单壁氮化硼纳米管的光学性质进行了理论研究。由梯度近似和随机相位近似计算的介电函数是一致的。介电函数的虚部和真实的部分别表现出特殊的峰和谷。在ω < 4处有很强的电子-氢吸收峰，γ（0）来自π带，其它的来自π + σ带（γ（0）是2 p（z）轨道的最近邻相互作用）。这样的单粒子激发也诱导反射光谱中的峰结构。另一方面，损失函数示出了突出的pi-和pi + σ-等离子体激元峰。π和π + σ等离子体激元（集体激发）在反射光谱中表现为强烈而突然的边缘。光学性质受偏振方向和纳米管半径的影响，但不受手征角的影响。计算结果可以通过光谱或EELS进行实验检查。
Optical properties of single-walled boron nitride nanotubes have been studied theoretically. The dielectric functions calculated from the gradient approximation and the random-phase approximation are consistent with each other. The imaginary and the real parts of the dielectric function, respectively, exihibit the special peaks and dips. The strong e-h absorption peaks at omega < 4 gamma(0) Comes from the pi band and the others from the pi + sigma bands (gamma(0) is the nearest-neighbor interaction of 2p(z) orbitals). Such single-particle excitations also induce the peak structures in the reflectance spectrum. On the other hand, the loss function shows the prominent pi- and pi + sigma-plasmon peaks. The pi and pi + sigma plasmons (collective excitations) reveal themselves in the reflectance spectrum as strong and abrupt edges. The optical properties are affected by the polarization direction and the nanotube radius, but not the chiral angle. The calculated results could be experimentally checked with optical spectroscopies or EELS.