微量子腔结边电荷极化结构中的线性和二阶非线性动态电导性质的研究

A study of linear and the second nonlinear admittance about the charge polarization around junction-boundaries in a quantum cavity structure

采用有效哈密顿量和有相互作用的分立势模型 ,利用格林函数和耦合参量得出了量子点 (腔 )在有结边电荷积累极化时的线性和二阶非线性交流电导虚部 (emittance)的明确表达式 .发现在经典情况下 ,电导虚部和电化学电容都等于经典的几何电容 .在非经典情况下 ,如果发生全反射 ,电导虚部和电化学电容相等 ,但两者皆不等于经典的几何电容 .在有隧穿的情况下 ,电导虚部和电化学电容以及经典电容三者都不相等 .

We present explicit expressions for the linear and the second nonlinear imaginar y parts of admittanc (emittance) for the charge polarization of accumulation on b oth sides of the quantum dot (cavity) junctions by using Green function and the c oupling parameters in an effective Hamiltonian and the discrete potential model. We found that the emittance and the electrochemical capacitance are equal to the g eometric capacitance in the classical limit. In the nonclassical case the emitta nce is equal to the electrochemical capacitance, but not equal to the geometr i c capacitance if there is complete reflection. In the case where there is tu nneling the emittance and electrochemical capacitance as well as the geometric c apacitance are different. The results may be helpful for measurements on capacit ance on small_scale structures.