Sharp peaks in the conductance of a double quantum dot and a quantum-dot spin valve at high temperatures: A hierarchical quantum master equation approach
Sharp peaks in the conductance of a double quantum dot and a quantum-dot spin valve at high temperatures: A hierarchical quantum master equation approach
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DOI：
10.1103/physrevb.94.121303
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发表时间：
2016-05
影响因子：
3.7
通讯作者：
Sebastian Wenderoth;Jakob Batge;R. Hartle
中科院分区：
文献类型：
--
作者：
Sebastian Wenderoth;Jakob Batge;R. Hartle
我们研究了双量子点和量子点自旋阀在零偏压附近的电导-电压特性的尖峰。这些峰与近藤峰有相似之处，但可以清楚地区分，特别是当它们在高温下发生时。潜在的物理机制是强电流抑制，其通过交换相互作用以偏置电压依赖的方式猝灭。我们的理论结果是基于量子主方程的方法，包括玻恩-马尔可夫近似和一个数值精确的，分层的计划，我们在这里扩展到自旋阀的情况下。精确和近似结果的比较使我们能够揭示潜在的物理机制，一阶，二阶和超越二阶过程的作用和效果的鲁棒性。
We study sharp peaks in the conductance-voltage characteristics of a double quantum dot and a quantum dot spin valve that are located around zero bias. The peaks share similarities with a Kondo peak but can be clearly distinguished, in particular as they occur at high temperatures. The underlying physical mechanism is a strong current suppression that is quenched in bias-voltage dependent ways by exchange interactions. Our theoretical results are based on the quantum master equation methodology, including the Born-Markov approximation and a numerically exact, hierarchical scheme, which we extend here to the spin-valve case. The comparison of exact and approximate results allows us to reveal the underlying physical mechanisms, the role of first-, second- and beyond-second-order processes and the robustness of the effect.