Nonequilibrium Kondo effect in a multilevel quantum dot near the singlet-triplet transition
Nonequilibrium Kondo effect in a multilevel quantum dot near the singlet-triplet transition
复制标题
多级量子点中单重态-三重态跃迁附近的非平衡近藤效应
DOI：
10.1103/physrevb.66.113310
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发表时间：
2002
影响因子：
3.7
通讯作者：
X. Lei
中科院分区：
文献类型：
--
作者：
B. Dong;X. Lei
利用广义有限U从玻色子平均场方法研究了通过连接两个引线的多能级横向量子点的线性和非线性输运。对于二能级量子点，我们的计算表明，在自旋单重态和三重态的简并点附近，电导的非单调温度依赖性，以及微分电导的急剧下降和非零偏置最大值的显着电导增强。这与最近的实验观察结果吻合得很好。这种两阶段的近藤效应在一个非平衡的情况下归因于两个能级之间的干扰。
The linear and nonlinear transport through a multilevel lateral quantum dot connected to two leads is investigated using a generalized finite-$U$ slave-boson mean-field approach. For a two-level quantum dot, our calculation demonstrates a substantial conductance enhancement near the degeneracy point of the spin singlet and triplet states, a nonmonotonic temperature dependence of conductance, and a sharp dip and nonzero bias maximum of the differential conductance. These agree well with recent experiment observations. This two-stage Kondo effect in an out-of-equilibrium situation is attributed to the interference between the two energy levels.