New approach to the physics of two dimensional electron systems

通过样品相对于磁场的原位倾斜，研究了高迁移率硅二维电子系统中的磁输运。在非整数填充因子的朗道水平交叉过程中，观察到了纵向电阻率的显著下降。这表明相关朗道能级中的电子在重合处发生局域化。对于高迁移率的Si/SiGe材料，在低温下研究了二维电子的回旋共振，发现了金属温度对直流电阻率的依赖关系。弛豫时间表现出与输运散射时间类似的负温度依赖关系。用磁输运测量方法研究了解理面单原子层Pb膜的二维超导电性。这一结果是根据对具有较大Rashba自旋分裂的2D金属所预测的非均匀超导状态来解释的。

We study magnetotransport in a high-mobility Si two-dimensional electron system by in situ tilting of the sample relative to the magnetic field. A pronounced dip in the longitudinal resistivity is observed during the Landau-level crossing process for noninteger filling factors. This indicates that electrons in the relevant Landau levels become localized at the coincidence.Cyclotron resonance of two-dimensional electrons is studied at low temperatures for a high-mobility Si/SiGe which exhibits a metallic temperature dependence of dc resistivity. The relaxation time shows a negative temperature dependence, which is similar to that of the transport scattering time.Two-dimensional (2D) superconductivity was studied by magnetotransport measurements on single-atomic-layer Pb films on a cleaved GaAs surface. The results are explained in terms of an inhomogeneous superconducting state predicted for 2D metals with a large Rashba spin splitting.