Spatial distribution of thermoelectric voltages in a Hall-bar shaped two-dimensional electron system under a magnetic field
Spatial distribution of thermoelectric voltages in a Hall-bar shaped two-dimensional electron system under a magnetic field
复制标题
磁场下霍尔条形二维电子系统热电电压的空间分布
DOI：
10.1088/2399-6528/ab1add
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Y. Iye
中科院分区：
文献类型：
--
作者：
A. Endo;K. Fujita;S. Katsumoto;Y. Iye
研究了垂直磁场作用下二维电子系统（2DES）中电子温度的空间分布。我们测量了由GaAs/AlGaAs 2DES晶圆制成的霍尔棒的电压探针臂末端的欧姆触点之间的热电电压，浸入稀释冰箱的混合室中，温度为20 mK。由于朗道量子化而引起的磁振荡被检查了跨在主棒上的接触对之间的热电电压（布置以测量横向分量vyx）。以及位于主杆同一侧的对之间（纵向组件V xx的布置）。对于前一种布置，振荡幅度随着与加热器的距离而减小。对于后一种排列，一侧的对表现出比另一侧的对大得多的振幅，并且这种关系通过反转磁场而逆转。考虑到电压触点的热扩散和电子-声子相互作用，用数值计算的电子温度的空间分布定性地解释了振荡幅度的行为。对于这两种排列，显示振荡主要来自热功张量的横向（能）分量，S x。计算还表明，电压探头在零磁场下只会产生很小的扰动，一旦施加磁场就会大大降低温度，并且在电压臂上产生的热电电压占测量电压的很大一部分。
We have investigated the spatial distribution of the electron temperature generated in a two-dimensional electron system (2DES) subjected to a perpendicular magnetic field. We measure thermoelectric voltages between Ohmic contacts located at the end of the voltage-probe arms of a Hall bar fabricated from a GaAs/AlGaAs 2DES wafer, immersed in the mixing chamber of a dilution refrigerator held at 20 mK. Magneto-oscillations due to the Landau quantization are examined for the thermoelectric voltages between the contact pairs straddling the main bar (arrangement to measure the transverse component V yx), and between the pairs located along the same side of the main bar (arrangement for the longitudinal component V xx). For the former arrangement, the oscillation amplitude diminishes with the distance from the heater. For the latter arrangement, the pair on one side exhibits much larger amplitude than the pair on the opposite side, and the relation becomes reversed by inverting the magnetic field. The behaviours of the oscillation amplitude are qualitatively explained by the spatial distribution of the electron temperature numerically calculated taking into consideration the thermal diffusion into the voltage contacts and the electron-phonon interaction. For both arrangements, the oscillations are shown to derive predominantly from the transverse (Nernst) component, S yx, of the thermopower tensor. The calculation also reveals that the voltage probes, introducing only minor disturbance at zero magnetic field, substantially reduce the temperature once a magnetic field is applied, and the thermoelectric voltages generated at the voltage arms account for a significant part of the measured voltages.
登录
查看更多内容
DOI：
10.1063/1.1721725
发表时间：
1954
期刊：
影响因子：
--
作者：
R. Wick
通讯作者：
R. Wick
量子霍尔系统中扩散热电势的测量
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
K.Fujita;A.Endo;S.Katsumoto;Y.Iye
通讯作者：
Y.Iye
DOI：
--
发表时间：
1999
期刊：
影响因子：
--
作者：
A. Yacoby;H. Hess;T. Fulton;L. Pfeiffer;K. West
通讯作者：
K. West
介观二维电子系统中反常能斯特效应的特征
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
S. Goswami;C. Siegert;M. Pepper;I. Farrer;D. Ritchie;A. Ghosh
通讯作者：
A. Ghosh
DOI：
10.1016/0038-1098(87)90177-3
发表时间：
1987
期刊：
影响因子：
--
作者：
B. Neudecker;K. Hoffmann
通讯作者：
K. Hoffmann