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arXiv 0810.3713cond-mat.mes-hall
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二维电子在交叉电场和磁场中的非线性电阻

Nonlinear resistance of 2D electrons in crossed electric and magnetic fields

Jing Qiao Zhang, Sergey Vitkalov, A. A. Bykov

摘要:

强磁场中的二维电子的纵向电阻率被外加电场显著地降低,在具有高电子密度的GaAs量子阱中,在宽范围的磁场和温度下研究了这种效应。数据被发现是在良好的协议与理论,考虑到强非线性的电阻率作为结果的非均匀光谱扩散的二维电子。非弹性过程限制了扩散。通过与理论的比较,得到了二维电子的非弹性散射时间。在T=2-10(K)的温度范围内,对于重叠的朗道能级,发现非弹性散射率与T^2成正比,表明电子-电子散射对非弹性弛豫的主要贡献。在强磁场中,非线性电阻率表现出标度行为,表明分离良好的朗道能级的电子加热的特定制度。在这种情况下,非弹性散射率与T^3成正比,这表明电子-声子散射是非弹性弛豫的主要机制。

英文摘要:

The longitudinal resistivity of two dimensional (2D) electrons placed in strong magnetic field is significantly reduced by applied electric field, an effect which is studied in a broad range of magnetic fields and temperatures in GaAs quantum wells with high electron density. The data are found to be in good agreement with theory, considering the strong nonlinearity of the resistivity as result of non-uniform spectral diffusion of the 2D electrons. Inelastic processes limit the diffusion. Comparison with the theory yields the inelastic scattering time of the two dimensional electrons. In the temperature range T=2-10(K) for overlapping Landau levels, the inelastic scattering rate is found to be proportional to T^2, indicating a dominant contribution of the electron-electron scattering to the inelastic relaxation. In a strong magnetic field, the nonlinear resistivity demonstrates scaling behavior, indicating a specific regime of electron heating of well-separated Landau levels. In this regime the inelastic scattering rate is found to be proportional to T^3, suggesting the electron-phonon scattering as the dominant mechanism of the inelastic relaxation.

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