Kondo effect in double quantum dots with ferromagnetic RKKY interaction
Kondo effect in double quantum dots with ferromagnetic RKKY interaction
复制标题
铁磁 RKKY 相互作用双量子点中的近藤效应
DOI：
10.1088/0953-8984/29/2/025601
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Yan YiJing
中科院分区：
文献类型：
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作者：
Pan Lei;Wang YuanDong;Li ZhenHua;Wei JianHua;Yan YiJing
用精确的非微扰层次运动方程方法研究了具有铁磁性Ruderman-Kittel-Kasuya-Yoshida(RKKY)相互作用的平行耦合双量子点中的近藤效应。我们构造了点间耦合t和铁磁交换相互作用J(J−4T2/U平面)参数平面上的相图。图中确定了近藤单态、自旋单态和S=1近藤三种不同的基态。我们发现铁磁耦合将在有限跳跃t区域内提高近藤峰，这被称为“J增强近藤效应”。还给出了J=0时t(t增强的Kondo效应)对Kondo效应的另一种增强。通过检验电子-电子相互作用的自能和磁化率，验证了大J基态是由剩余自旋为1/2的费米液体组成的欠屏蔽Kondo态，这与文献中的“奇异费米液体态”是一致的。
We study Kondo effect in parallel-coupled double quantum dots with ferromagnetic Ruderman–Kittel–Kasuya–Yoshida (RKKY) interaction, by using the exact and nonperturbative hierarchical equations of motion approach. We construct the phase diagram in the parameter plane of the inter-dot coupling t and the ferromagnetic exchange interaction J (J− 4t 2/U plane). Three different ground states, the Kondo singlet, spin singlet and S= 1 Kondo, are determined in the diagram. We find the ferromagnetic coupling will raise the Kondo peak in the area of finite hopping t which is called'J-enhanced Kondo effect'. Another enhancement of the Kondo effect by t ('t-enhanced Kondo effect') at J= 0 is also presented. By checking the electron–electron interaction self-energy and magnetic susceptibility, we verify the ground state at large J is an under-screening Kondo state composed of a Fermi liquid with a residual spin 1/2, which is consistent with the'singular Fermi liquid state'in the literature.