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Spin Sensitive Temperature Dependence of the Landau Levels in the Quantum Hall Regime

量子霍尔体系中朗道能级的自旋敏感温度依赖性

基本信息

批准号：
10640315
负责人：
WAKABAYASHI Junichi
金额：
$ 1.09万
依托单位：
Chuo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640315/
关键词：
Integer Quantum Hall Effect Distributed Magnetic Field Spin Splitting Landua Levels Temperature Dependence

项目摘要

Temperature dependence of the transition region between the quantum Hall plateaus has been measured at temperature between 50 mK and 1.8 K using a high mobility(110 mィイD12ィエD1/Vs) and two low mobility (〜18 mィイD12ィエD1/Vs) GaAs/AlGaAs hetero samples. V-shaped magnetic field distribution was produced by placing a single crystal platelet of a high Tc super conductor. We have found spin dependent temperature dependence of the spin split Landau levels. Landau levels with spin down have shown a shift of the transition region to the higher magnetic field when the temperature was increased during the field up process. Landau levels with spin up, on the other hand, have shown the temperature dependence as same as the normal sample, I.e., no effect of the magnetic field distribution was found. We have found these spin dependent temperature dependence occurs in the Landau levels with different Landau quantum number and both in samples with high and low mobility sample and, hence, the phenomenon is quite general. Further, when the magnetic field distribution was reversed by decreasing the magnetic field, spin dependence of the temperature dependence was symmetrically interchanged, I.e., Landau levels with spin up have shown a shift of the transition region to the lower magnetic field when the temperature was increased. There is no theory to explain these phenomena at present.

用一个高迁移率(110mィイD12ィエd1/vs)和两个低迁移率(~18mィイd12ィエd1/vs)的异质结样品，在50mK到1.8K温度范围内测量了量子霍尔平台之间过渡区的温度依赖关系。通过放置高T_c超导体的单晶片，产生了V形磁场分布。我们发现自旋分裂朗道能级与自旋温度有关。随自旋下降的朗道能级在磁场上升过程中，随着温度的升高，过渡区向高磁场方向移动。另一方面，随自旋上升的朗道能级表现出与正常样品相同的温度依赖关系，即没有发现磁场分布的影响。我们发现在不同朗道量子数的朗道能级以及具有高和低迁移率样品的朗道能级中都存在这种与自旋有关的温度依赖关系，因此，这种现象是非常普遍的。进一步地，当降低磁场使磁场分布反转时，温度依赖的自旋依赖关系被对称地交换，即随自旋上升的朗道能级随温度升高而向低磁场方向移动。目前还没有理论来解释这些现象。