Goldozian Bahareh, Damtie Fikeraddis A, Kiršanskas Gediminas, Wacker Andreas
Mathematical Physics and NanoLund, Lund University, Box 118, S-22100 Lund, Sweden.
Sci Rep. 2016 Mar 7;6:22761. doi: 10.1038/srep22761.
Quantum dots are nanoscopic systems, where carriers are confined in all three spatial directions. Such nanoscopic systems are suitable for fundamental studies of quantum mechanics and are candidates for applications such as quantum information processing. It was also proposed that linear arrangements of quantum dots could be used as quantum cascade laser. In this work we study the impact of electron-electron interactions on transport in a spinful serial triple quantum dot system weakly coupled to two leads. We find that due to electron-electron scattering processes the transport is enabled beyond the common single-particle transmission channels. This shows that the scenario in the serial quantum dots intrinsically deviates from layered structures such as quantum cascade lasers, where the presence of well-defined single-particle resonances between neighboring levels are crucial for device operation. Additionally, we check the validity of the Pauli master equation by comparing it with the first-order von Neumann approach. Here we demonstrate that coherences are of relevance if the energy spacing of the eigenstates is smaller than the lead transition rate multiplied by ħ.
量子点是纳米级系统，其中载流子在所有三个空间方向上都受到限制。这种纳米级系统适用于量子力学的基础研究，并且是诸如量子信息处理等应用的候选者。还有人提出量子点的线性排列可以用作量子级联激光器。在这项工作中，我们研究了电子-电子相互作用对与两个引线弱耦合的自旋串联三量子点系统中输运的影响。我们发现，由于电子-电子散射过程，输运能够通过常见的单粒子传输通道之外的通道进行。这表明串联量子点中的情况本质上不同于诸如量子级联激光器的层状结构，在量子级联激光器中，相邻能级之间明确的单粒子共振的存在对于器件运行至关重要。此外，我们通过将泡利主方程与一阶冯·诺依曼方法进行比较来检验其有效性。在此我们证明，如果本征态的能量间距小于引线跃迁速率乘以ħ，则相干性是相关的。
