Conductance dip in the Kondo regime of linear arrays of quantum dots
Conductance dip in the Kondo regime of linear arrays of quantum dots
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DOI：
10.1103/physrevb.70.035402
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发表时间：
2003-08
影响因子：
3.7
通讯作者：
C. Busser;A. Moreo;E. Dagotto
中科院分区：
文献类型：
--
作者：
C. Busser;A. Moreo;E. Dagotto
利用小团簇的精确对角化和Dyson方程嵌入技术，研究了线性量子点阵列的电导。Hubbard相互作用在低温下产生奇数个点的近藤峰。值得注意的是，近藤的峰值被深极小值一分为二，电导在栅极电压的一个值处消失。对这种不寻常的效应提出了初步的解释，包括两个通道之间的干涉过程对$G$的贡献，比精确求解的团簇基态多一个粒子和少一个粒子。电子的哈伯德相互作用和费米子统计似乎对理解这一现象也很重要。虽然大多数计算使用的是粒子-空穴对称的哈密顿量和形式，但本文的结果也表明，即使在这种对称性被破坏的情况下，也存在电导凹陷。用数值方法得到的电导抵消效应是很有趣的，应该用其他多体技术来证实它的存在。
Using exact-diagonalization of small clusters and Dyson equation embedding techniques, the conductance $G$ of linear arrays of quantum dots is investigated. The Hubbard interaction induces Kondo peaks at low temperatures for an odd number of dots. Remarkably, the Kondo peak is split in half by a deep minimum, and the conductance vanishes at one value of the gate voltage. Tentative explanations for this unusual effect are proposed, including an interference process between two channels contributing to $G$, with one more and one less particle than the exactly-solved cluster ground-state. The Hubbard interaction and fermionic statistics of electrons also appear to be important to understand this phenomenon. Although most of the calculations used a particle-hole symmetric Hamiltonian and formalism, results also presented here show that the conductance dip exists even when this symmetry is broken. The conductance cancellation effect obtained using numerical techniques is potentially interesting, and other many-body techniques should be used to confirm its existence.