Nonideal effects in quantum field-effect directional coupler
Xie Yue-E(谢月娥)a), Yan Xiao-Hong(颜晓红)b)†, and Chen Yuan-Ping(陈元平)a)
a Institute of Modern Physics and Department of Physics, Xiangtan University, Xiangtan 411105, China; b College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Abstract The nonideal effects in a quantum field-effect directional coupler where two quantum wires are coupled through a finite potential barrier are studied by adopting the lattice Green function method. The results show that the electron energy distribution, asymmetric geometry and finite temperature all have obvious influence on the electron transfer of the coupler. Only for the electrons with energies in a certain region, can the complete periodic transfer between two quantum wires take place. The conductance of these electrons as a function of the barrier length and potential height exhibits a fine periodic or quasi-periodic pattern. For the electrons with energies beyond the region, however, the complete periodic transfer does not hold any more since many irregular oscillations are superimposed on the conductance profile. In addition, the finite temperature and asymmetric geometry both can reduce the electron transfer efficiency.
Received: 09 June 2005
Revised: 11 June 2006
Accepted manuscript online:
Fund: Project supported by the
Project of Hunan Provincial Education Ministry (Grant No 05C103) and the
Research Fund of National
Education Ministry of China (Grant No
204099).
Cite this article:
Xie Yue-E(谢月娥), Yan Xiao-Hong(颜晓红), and Chen Yuan-Ping(陈元平) Nonideal effects in quantum field-effect directional coupler 2006 Chinese Physics 15 2415
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