发表机构
School of Physics and Astronomy, Seoul National University（首尔大学物理与天文学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究根据自旋动力学和标度函数，将纳米电子器件的相干峰分为两类，明确了两类零偏置峰的本质差异，并通过理论重现验证了QDSET奇数粒子区零偏置峰是两个相干侧峰合并的结论。
AI 中文摘要
量子点单电子晶体管（QDSET）和量子点接触（QPC）器件的微分电导中出现的相干峰，根据温度标度后的微分电导最大值所塌缩到的标度函数以及潜在的自旋动力学，被分为两类。在QPC中以及QDSET的偶数粒子区的三重态中观测到的零偏置峰（ZBP）属于同一类别；而QDSET奇数粒子区的ZBP则与在QPC中以及QDSET偶数粒子区观测到的所有有限偏置相干峰属于另一类别。前一类的自旋动力学涉及自旋交换，这是近藤动力学（Kondo dynamics）的标志；而后一类的自旋动力学仅涉及自旋向上-向下对的共隧穿。此外，对于前一类ZBP，其标度温度等于半高全宽（FWHM）的一半，对应近藤温度；而对于后一类，标度温度与由1/2 FWHM导出的能量尺度不重合。为验证这些发现，本文从理论上重现了QDSET奇数粒子区测得的栅极电压依赖的微分电导线形。结果表明，观测到的ZBP是仅由自旋向上-向下对的共隧穿产生的两个相干侧峰合并而成的。
英文摘要
Coherent peaks appearing in the differential conductance of quantum-dot single-electron transistors (QDSETs) and quantum point contact (QPC) devices are classified into two categories according to the scaling function onto which the temperature-scaled differential-conductance maxima collapse and the underlying spin dynamics. The zero-bias peaks (ZBPs) observed in QPCs and in the triplet state of the even-particle sector of QDSETs belong to the same category, whereas the ZBP in the odd-particle sector of a QDSET belongs to a different category together with all finite-bias coherent peaks observed in QPCs and in the even-particle sector of QDSETs. The spin dynamics of the former category involve spin exchange, a hallmark of Kondo dynamics, whereas those of the latter category involve only cotunneling of an up--down spin pair. Furthermore, for the former type of ZBP, the scaling temperature coincides with one-half of the full width at half maximum (FWHM), which corresponds to the Kondo temperature. In contrast, for the latter type, the scaling temperature does not coincide with the (1/2)FWHM-derived energy scale. To support these findings, the gate-voltage-dependent differential-conductance line shapes measured in the odd-particle sector of a QDSET are theoretically reproduced. The results demonstrate that the observed ZBP is a merging of two coherent side peaks generated solely by the cotunneling of up--down spin pairs.
Comments15 pages, 8 figures
