Institut für Theoretische Physik A, RWTH Aachen, 52056 Aachen, Germany.
Phys Rev Lett. 2009 Oct 9;103(15):156803. doi: 10.1103/PhysRevLett.103.156803. Epub 2009 Oct 7.
We predict a new electron pair tunneling (PT) resonance in nonlinear transport through quantum dots with positive charging energies exceeding the broadening due to thermal and quantum fluctuations. The PT resonance shows up in the single-electron transport (SET) regime as a peak in the derivative of the nonlinear conductance, d(2)I/dV(2), when the electrochemical potential of one electrode matches the average of two subsequent charge addition energies. For a single level quantum dot (Anderson model) we find the analytic peak shape and the dependence on temperature, magnetic field, and junction asymmetry and compare with the inelastic cotunneling peak which is of the same order of magnitude. In experimental transport spectroscopy the PT resonance may be mistaken for a weak SET resonance judging only by the voltage dependence of its position. Our results provide essential clues to avoid such erroneous interpretation.
我们预测在具有正充电能量的量子点中，通过非线性输运存在新的电子对隧穿（PT）共振，该能量超过了热和量子涨落引起的展宽。在单电子输运（SET）区，当一个电极的电化学势与随后两次电荷增加能量的平均值匹配时，在非线性电导的导数 d(2)I/dV(2)中出现 PT 共振峰。对于单个能级量子点（安德森模型），我们找到了分析得出的峰形状以及对温度、磁场和结不对称性的依赖性，并与同等数量级的非弹性库仑隧道峰进行了比较。在实验传输谱中，仅根据其位置的电压依赖性，PT 共振可能会被误认为是较弱的 SET 共振，从而导致错误的解释。我们的结果为避免这种错误解释提供了重要线索。
