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arXiv 0709.3625cond-mat.mes-hall
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横向耦合场诱导量子霍尔系统

Laterally coupled and field-induced quantum Hall systems

Matthias Habl, Werner Wegscheider

摘要:

通过隧穿势垒将量子霍尔系统分成两个横向耦合的子系统,系统表现出复杂的朗道能级色散。磁隧穿光谱被用来研究分离随后的朗道带的小能隙。对费米能级的控制允许跟踪不同磁场的反交叉。的能带结构计算预测的回旋能量的尺度上的带隙的磁位移。这种效果通过填充因子轴上的电导峰的位移实验证实。势垒内的隧穿中心负责相对边缘通道之间的量子干涉。由于无序势,相应的Aharonov-Bohm干涉仪产生额外的长周期和不规则的电导特征。在强局域化的制度,电导波动发生在小磁场的发病前,定期朗道振荡。朗道色散是由一个专用的算法,解决了薛定谔方程精确地为一个单电子驻留在一个量子霍尔系统与任意单向,三重阶梯势。

英文摘要:

A quantum Hall system which is divided into two laterally coupled subsystems by means of a tunneling barrier exhibits a complex Landau level dispersion. Magnetotunneling spectroscopy is employed to investigate the small energy gaps which separate subsequent Landau bands. The control on the Fermi level permits to trace the anticrossings for varying magnetic fields. The band structure calculation predicts a magnetic shift of the band gaps on the scale of the cyclotron energy. This effect is confirmed experimentally by a displacement of the conductance peaks on the axis of the filling factor. Tunneling centers within the barrier are responsible for quantum interferences between opposite edge channels. Due to the disorder potential, the corresponding Aharonov-Bohm interferometers generate additional long-period and irregular conductance features. In the regime of strong localization, conductance fluctuations occur at small magnetic fields before the onset of the regular Landau oscillations. The Landau dispersion is obtained by a dedicated algorithm which solves the Schroedinger equation exactly for a single electron residing in a quantum Hall system with an arbitrary unidirectional, threefold staircase potential.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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