Y型量子线中电子弹道输运性质

对有限长Y型量子线中的电子弹道输运性质进行了量子力学计算．该有限长的量子结构分与两半无限长的量子通道相连，当施加一偏压时，量子通道分别可作为电子的发射极和收集极．采用了转移矩阵方法和截断近似技术．计算结果表明，当结构对于x轴对称时，在入射电子的能量小于量子结构的第一个横向本征模时，电导存在着两个峰；当结构对于x轴不对称时，电导则存在着三个峰．进一步分析表明，这些峰来自于电子共振隧穿量子结构中的量子束缚态．该结构对于经典粒子来说是非束缚体系．当结构对于x轴对称时，较高能级是双重简并的，而当结构对于x轴不对称时，该能级的简并度消除．

Ballistic Transport in Y-Typed Quantum Channels

The quantum-mechanical calculations of ballistic transport in finite Y-typed quantum channels are carried out.The channels connect to two semi-infinite quantum channels,which serve as the emitter and collector respectively when a potential difference is applied.The calculations are based on the transfer-matrix method and a truncating approximation.The numerical results show that,when the structure is symmetry related to the x-direction,there exist two peaks in the conductance at the energy of electrons less than the eigenvalue of the first transverse mode,and,when the structure is asymmetry related to the x-direction,there exist three peaks.It must be pointed out that these peaks are due to the resonant tunneling via bound states in the quantum structure which is a classical unbound system.When the structure is symmetry related to the x-direction,the higher energy level has double degeneracy,otherwise the degeneracy of the level is removed.