Terahertz electromagnetic response and its electric field manipulation of bulked silicene
Terahertz electromagnetic response and its electric field manipulation of bulked silicene
复制标题
块状硅烯的太赫兹电磁响应及其电场操控
DOI：
10.1088/1612-2011/12/9/095902
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发表时间：
2015-09-01
影响因子：
1.7
通讯作者：
Zhou, Guanghui
中科院分区：
文献类型：
--
作者：
Bao, Hairui;Liao, Wenhu;Zhou, Guanghui
利用子带间跃迁定理，从理论上研究了三端硅烯器件在圆极化太赫兹(THz)电磁场辐照下的低温红外光学性质。研究表明，块状硅烯的电子结构可以通过背栅电压诱导的交错亚晶格势分别调谐到拓扑绝缘(TI)和带绝缘(BI)态。此外，随着交错亚晶格势的增强，TI态自旋上、下亚带的折射率、消光系数和光学电导分别发生红移和蓝移，而BI态自旋上、下亚带的折射率、消光系数和光学电导则连续蓝移。集体激发和单独的电子-空穴对激发产生了与折射率、消光系数和光学电导率类似的红移和/或蓝移的TI态和BI态电子能量损失谱。所得结果对基于硅烯的自旋电子器件和光电子器件的设计具有一定的参考价值。
We theoretically investigate the infrared optical properties of a three-terminal silicene-based device under the irradiation of a circularly polarized terahertz (THz) electromagnetic field, utilizing the intersubband transition theorem at low temperatures. It has been demonstrated that the electronic structure of bulked silicene can be tuned to the topological insulated (TI) and band insulated (BI) state, respectively, via the back-gate voltage induced staggered sublattice potential. Furthermore, with the enhancement of the staggered sublattice potential, the refractive index, extinction coefficient and optical conductivity from the TI state spin-up and -down subbands are observed to be red- and blue-shifted, respectively, while those from the BI state spin-up and -down subbands are proved to be continually blue-shifted. The collective excitations and individual electron–hole pair excitations induced a TI and BI state electron energy loss spectrum (EELS) with a similar red- and/or blue-shift behaviour as the refractive index, extinction coefficient and optical conductivity. The obtained results may be useful in the design of the spintronic and optoelectronic devices based on silicene.