Low-field diffusion magnetothermopower of a high-mobility two-dimensional electron gas
Low-field diffusion magnetothermopower of a high-mobility two-dimensional electron gas
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高迁移率二维电子气的低场扩散磁热发电
DOI：
10.1103/physrevb.70.121308
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发表时间：
2004
影响因子：
3.7
通讯作者：
Bochum
中科院分区：
文献类型：
--
作者：
S. Maximov;M. Gbordzoe;H. Buhmann;L. Molenkamp;D. Institut;U. Wuerzburg;H Germany;Lehrstuhl fuer Festkoerperphysik;Ruhr;Bochum
在低温（T = 1.6 K）、低磁场（B < 1.2 T）条件下，在离域量子霍尔态不影响测量结果的情况下，在静电定义的微米尺度霍尔棒结构上直接测量了高迁移率gaas异质结构的低磁场扩散热功率。样品设计允许确定平行和垂直于温度梯度的热功率的场依赖性，分别用Sxx（纵向热功率）和Syx（能斯特-埃廷豪森系数）表示。实验数据表明，在0.3 T < B < 1.2 T时，由于朗道能级的形成，Sxx和Syx中存在明显的振荡，并且表明在1 T磁场下，Syx比Sxx大约120倍，这与理论预测吻合得很好。
The low magnetic field diffusion thermopower of a high mobility GaAs-heterostructure has been measured directly on an electrostatically defined micron-scale Hall-bar structure at low temperature (T = 1.6 K) in the low magnetic field regime (B < 1.2 T) where delocalized quantum Hall states do not influence the measurements. The sample design allowed the determination of the field dependence of the thermopower both parallel and perpendicular to the temperature gradient, denoted respectively by Sxx (longitudinal thermopower) and Syx (Nernst-Ettinghausen coefficient). The experimental data show clear oscillations in Sxx and Syx due to the formation of Landau levels for 0.3 T < B < 1.2 T and reveal that Syx is approximately 120 times larger than Sxx at a magnetic field of 1 T, which agrees well with the theoretical prediction.