Liu Weici, Wang Faqiang, Tang Zhilie, Liang Ruisheng
Guangdong Research Center of Photoelectric Detection Instrument Engineering Technology, and Guangdong Laboratory of Quantum Engineering and Quantum Materials, School of physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
Department of Electronic Information Engineering, Guangzhou College of Technology and Business, Foshan 528138, China.
Nanomaterials (Basel). 2019 Jun 6;9(6):863. doi: 10.3390/nano9060863.
In a single quantum dot (QD) system connected with ferromagnetic electrodes, the electron transport properties, assisted by the thermal and Fock state optical fields, are theoretically studied by the Keldysh nonequilibrium Green's function approach. The results show that the evolution properties of the density of state and tunneling current assisted by the Fock state optical field, are quite different from those of the thermal state. The photon sideband shift decreases monotonously with the increase in the electron-photon coupling strength for the case of the thermal state, while the shift is oscillatory for the case of the Fock state. Negative differential conductance (NDC) appears obviously in a QD system contacted with parallel () and antiparallel () magnetization alignment of the ferromagnetic electrode leads, assisted by the Fock state optical field in a wide range of electron-photon interaction parameters. Evident NDC usually only arises in an configuration QD system assisted by the thermal state optical field. The results have the potential to introduce a new way to actively manipulate and control the single-electron tunneling transport on a QD system by the quantum states of the optical field.
在一个与铁磁电极相连的单量子点（QD）系统中，借助热场和福克态光场，采用凯尔迪什非平衡格林函数方法对电子输运性质进行了理论研究。结果表明，福克态光场辅助下的态密度和隧穿电流的演化特性与热态的截然不同。对于热态情况，光子边带位移随电子 - 光子耦合强度的增加单调减小，而对于福克态情况，该位移是振荡的。在福克态光场辅助下，在很宽的电子 - 光子相互作用参数范围内，与铁磁电极引线的平行（）和反平行（）磁化排列相接触的量子点系统中明显出现负微分电导（NDC）。明显的负微分电导通常仅在热态光场辅助下的 构型量子点系统中出现。这些结果有可能引入一种新方法，通过光场的量子态来主动操纵和控制量子点系统上的单电子隧穿输运。
