Photoinduced pseudospin effects in silicene beyond the off-resonant condition
Photoinduced pseudospin effects in silicene beyond the off-resonant condition
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DOI：
10.1103/physrevb.91.125105
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发表时间：
2015-03-02
影响因子：
3.7
通讯作者：
Schliemann, John
中科院分区：
文献类型：
--
作者：
Lopez, Alexander;Scholz, Andreas;Schliemann, John
研究了太赫兹电磁辐射下单层硅烯中载流子的光诱导操纵。在Dirac锥近似下，我们超越了只允许虚光子过程的大频率辐射场的非共振条件，给出了精确的零动量赝自旋极化和准能带结构及时均态密度的数值结果.我们发现，共振过程，由于真实的光子发射和吸收过程，诱导带反转，定性修改quasienergy频谱。这些能带结构的变化表现为平均赝自旋极化的反转。通过对时均态密度的分析，我们发现有效的光生能隙操纵只能在非共振近似失效的中强物质-辐射耦合区实现。
We study the photoinduced manipulation of charge carriers in monolayer silicene subject to intense electromagnetic terahertz radiation. Considering the Dirac cone approximation and going beyond the off-resonant condition for large frequencies of the radiation field, where only virtual photon processes are allowed, we present the exact zero-momentum pseudospin polarization and numerical results for the quasienergy band structure and time-averaged density of states. We find that resonant processes, due to real photon emission and absorbtion processes, induce a band inversion that qualitatively modifies the quasienergy spectrum. These band-structure changes manifest themselves as an inversion of the averaged pseudospin polarization. Through the analysis of the time-averaged density of states we find that effective photoinduced gap manipulation can only be achieved in the intermediate and strong matter-radiation coupling regime where the off-resonant approximation breaks down.