Magnetic splitting of the zero-bias peak in a quantum point contact with a tunable aspect ratio
Magnetic splitting of the zero-bias peak in a quantum point contact with a tunable aspect ratio
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具有可调纵横比的量子点接触中零偏置峰的磁分裂
DOI：
10.1103/physrevb.84.075320
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发表时间：
2009
影响因子：
3.7
通讯作者：
M. Melloch
中科院分区：
文献类型：
--
作者：
Tai;Bryan Hemingway;A. Kogan;S. Herbert;M. Melloch
我们报道了在外加磁场中分裂的量子点接触(QPC)的微分电导中的零偏压峰。在从$2e^2/h$开始的器件电导值范围内观察到该峰值。观测到的劈裂与塞曼能很好地匹配，并且几乎不依赖于栅极电压，这表明峰的形成机制与电子自旋有关。实验的精确塞曼能量数据是从一个单独图案化的单电子晶体管获得的，该晶体管位于离QPC不远的地方。该QPC器件具有四个栅极，其布置方式允许纵向电势可调，并且是在包含二维电子气的GaAs/AlGaAs异质结中制造的。我们表明，对于QPC势的适度扭曲，峰分裂和塞曼能量之间的一致性是稳健的。我们还发现，ZBP的形成机制不同于量子点中常见的近藤效应。
We report a zero-bias peak in the differential conductance of a Quantum Point Contact (QPC), which splits in an external magnetic field. The peak is observed over a range of device conductance values starting significantly below $2e^2/h$. The observed splitting closely matches the Zeeman energy and shows very little dependence on gate voltage, suggesting that the mechanism responsible for the formation of the peak involves electron spin. Precision Zeeman energy data for the experiment are obtained from a separately patterned single-electron transistor located a short distance away from the QPC. The QPC device has four gates arranged in a way that permits tuning of the longitudinal potential, and is fabricated in a GaAs/AlGaAs heterostructure containing 2-dimenional electron gas. We show that the agreement between the peak splitting and the Zeeman energy is robust with respect to moderate distortions of the QPC potential. We also show that the mechanism that leads to the formation of the ZBP is different from the conventional Kondo effect found in quantum dots.