中国物理B ›› 1994, Vol. 3 ›› Issue (10): 769-779.doi: 10.1088/1004-423X/3/10/007

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QUANTUM PERCOLATION AND BALLISTIC CONDUCTANCE IN A SYSTEM OF DOUBLE-COUPLED CHAINS

顾本源1, 杨国桢1, 范旭东2, 林宗涵3   

  1. (1)Institute of Physics, Academia Sinica, Beijing 100080, China; (2)Mesoscopic Physics Laboratory, Department of Physics, Peking University, Beijing 100871, China; (3)Mesoscopic Physics Laboratory, Departraent of Physics, Peking University, Beijing 100871, China and Institute of Theoretic Physics, Academia Sinica, Beijing 100080, China
  • 收稿日期:1993-11-16 出版日期:1994-10-20 发布日期:1994-10-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China and in part by the Chinese Academy of Sciences under the Grant LWTZ-1298.

QUANTUM PERCOLATION AND BALLISTIC CONDUCTANCE IN A SYSTEM OF DOUBLE-COUPLED CHAINS

FAN XU-DONG (范旭东)a, GU BEN-YUAN (顾本源)b, YANG GUO-ZHEN (杨国桢)b, LIN ZONG-HAN (林宗涵)c   

  1. a Mesoscopic Physics Laboratory, Department of Physics, Peking University, Beijing 100871, China ; b Institute of Physics, Academia Sinica, Beijing 100080, China; c Mesoscopic Physics Laboratory, Departraent of Physics, Peking University, Beijing 100871, China and Institute of Theoretic Physics, Academia Sinica, Beijing 100080, China
  • Received:1993-11-16 Online:1994-10-20 Published:1994-10-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China and in part by the Chinese Academy of Sciences under the Grant LWTZ-1298.

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摘要： The quantum-mechanical calculation of electronic conductance in double-coupled chains as a function of the interchain bonding probability p is presented. The calculated results show that one still can see the basic plateaus in the ensemble-averaged conductance curves as a function of the Fermi energy for the weak disorder. In addition, dense irregularly oscillating structures are superimposed upon each plateau. The characteristics of the conductance are very sensitive to the presence of the interchain broken bonds. For the strong disorder (p≈0.5) the conductance quantization breaks down. The accuracy of the quantization conductance rapidly drops down as the value of p approaches 0.5. The ensemble-averaged value of the logarithmic conductance as a function of the sample length exhibits a linear variation, determining a localization length. Both the localization length and the root-mean- square (RMS) value of the conductance fluctuations depend on p and the Fermi energy of electrons. The variations of the localization length and RMS with p are both of an approximate parabolic function around p≈0.5. No percolation transition is found for this quasi-one-dimensional system, as expected.

Abstract: The quantum-mechanical calculation of electronic conductance in double-coupled chains as a function of the interchain bonding probability p is presented. The calculated results show that one still can see the basic plateaus in the ensemble-averaged conductance curves as a function of the Fermi energy for the weak disorder. In addition, dense irregularly oscillating structures are superimposed upon each plateau. The characteristics of the conductance are very sensitive to the presence of the interchain broken bonds. For the strong disorder (p≈0.5) the conductance quantization breaks down. The accuracy of the quantization conductance rapidly drops down as the value of p approaches 0.5. The ensemble-averaged value of the logarithmic conductance as a function of the sample length exhibits a linear variation, determining a localization length. Both the localization length and the root-mean- square (RMS) value of the conductance fluctuations depend on p and the Fermi energy of electrons. The variations of the localization length and RMS with p are both of an approximate parabolic function around p≈0.5. No percolation transition is found for this quasi-one-dimensional system, as expected.

中图分类号:  (Conductivity phenomena in semiconductors and insulators)

  • 72.20.-i
03.65.-w (Quantum mechanics) 73.20.Fz (Weak or Anderson localization) 73.20.At (Surface states, band structure, electron density of states)