Department of Mathematics and Physics, North China Electric Power University, Beijing 102206, China.
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Sci Rep. 2017 Feb 22;7:42974. doi: 10.1038/srep42974.
Magnetic transport spectroscopy is investigated in quantum point contacts (QPCs) fabricated in AlGaN/GaN heterostructures. The magnetic field perpendicular to the two-dimensional electron gas (2DEG) is shown to depopulate the quasi-one-dimensional energy levels in the first two-dimensional (2D) subband faster than those in the second one. In GaN based heterostructures, the energy levels in the second 2D subband is generally concealed in the fast course of depletion and hence rarely detected. The perpendicular magnetic field facilitates the observation of the second 2D subband, and provides a method to study the properties of these energy levels. A careful analysis on the rate of the magnetic depletion with respect to the level index and confinement is carried out, from which the profile of the lateral confinement in GaN based QPCs is found to be triangular. The stability diagram at T shows the energy separation between the first and second 2D subband to be in the range of 32 to 42 meV.
在 AlGaN/GaN 异质结构中制造的量子点接触 (QPC) 中研究了磁输运谱。结果表明，与第二二维 (2D) 子带中的准一维能级相比，垂直于二维电子气 (2DEG) 的磁场更快地耗尽了第一个 2D 子带中的准一维能级。在基于 GaN 的异质结构中，第二 2D 子带中的能级通常在耗尽的快速过程中被掩盖，因此很少被检测到。垂直磁场有助于观察第二 2D 子带，并提供了研究这些能级性质的方法。通过仔细分析磁耗散与能级指数和限制的关系，发现基于 GaN 的 QPC 的横向限制的轮廓为三角形。在 T 处的稳定图显示，第一和第二 2D 子带之间的能量分离在 32 到 42 meV 的范围内。
