TRANSMISSION THROUGH BARRIERS AND RESONANT TUNNELING IN AN INTERACTING ONE-DIMENSIONAL ELECTRON-GAS
TRANSMISSION THROUGH BARRIERS AND RESONANT TUNNELING IN AN INTERACTING ONE-DIMENSIONAL ELECTRON-GAS
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DOI：
10.1103/physrevb.46.15233
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发表时间：
1992-12-15
影响因子：
3.7
通讯作者：
FISHER, MPA
中科院分区：
文献类型：
--
作者：
KANE, CL;FISHER, MPA
我们从理论上研究了一维单通道相互作用的电子气体通过障碍或收缩的输运。我们发现具有排斥性相互作用的电子，入射到单个势垒上，在零温度下完全反射。在有限温度(T)下，电导以T的幂函数形式消失，在零温度下，幂律电流-电压特性被预测。对于吸引相互作用，我们预测零温度下的完美传输，具有类似的幂律修正。我们还研究了通过双势垒结构的共振隧穿以及与库仑封锁相关的效应。如果相互作用的斥力不太强，则传输中的共振峰是可能的。然而，与非相互作用电子气体中的共振隧穿相反，我们发现在相互作用存在的情况下，共振宽度作为温度的幂函数在零温度极限下消失。此外，共振线的形状被证明是由一个通用尺度函数描述的，它具有幂律，但非洛伦兹尾。对于特定的相互作用强度选择，我们给出了模型的精确解，验证了尺度假设，并提供了尺度函数的显式表达式。我们还考虑了电子自旋自由度在改变势垒传输中所起的作用。对于自旋，电荷和自旋的完全透射或完全反射可能有四种相。我们给出了这些不同行为的相图，并分析了它们之间的重要转变。在这些过渡中，我们发现电导或传输是通用的——只取决于引线的无量纲电导，而不取决于障碍的细节。在自旋共振隧穿的情况下，我们讨论了当电子在两个势垒之间存在自旋简并时发生的“近藤”共振。许多预测应该可以在门控砷化镓线中直接测试。40378356
We study theoretically transport of a one-dimensional single-channel interacting electron gas through barriers or constrictions. We find that electrons with repulsive interactions, incident upon a single barrier, are completely reflected at zero temperature. At finite temperature (T), the conductance is shown to vanish as a power of T, and at zero temperature, power-law current-voltage characteristics are predicted. For attractive interactions, we predict perfect transmission at zero temperature, with similar power-law corrections. We also study resonant tunneling through a double-barrier structure and related effects associated with the Coulomb blockade. Resonant peaks in the transmission are possible, provided the interactions are not too strongly repulsive. However, in contrast to resonant tunneling in a noninteracting electron gas, we find that in the presence of interactions the width of the resonance vanishes, as a power of temperature, in the zero-temperature limit. Moreover, the resonance line shapes are shown to be described by a universal scaling function, which has power law, but non-Lorentzian tails. For a particular choice of interaction strengths, we present an exact solution of our model, which verifies the scaling assumptions and provides an explicit expression for the scaling function. We also consider the role played by the electron-spin degree of freedom in modifying the trasnsmission through barriers. With spin, there are four possible phases corresponding to perfect transmission or perfect reflection of charge and spin. We present phase diagrams for these different behaviors and analyze the nontrivial transitions between them. At these transitions we find that the conductance or transmission is universal-depending only on the dimensionless conductance of the leads and not on the details of the barriers. In the case of resonant tunneling with spin, we discuss the ''Kondo'' resonance, which occurs when there is a spin degeneracy for electrons between the two barriers. Many of the predictions should be directly testable in gated GaAs wires. 40378356