Current-Induced Cooling Phenomenon in a Two-Dimensional Electron Gas Under a Magnetic Field
Current-Induced Cooling Phenomenon in a Two-Dimensional Electron Gas Under a Magnetic Field
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DOI：
10.1007/s10909-012-0852-8
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发表时间：
2012-08
影响因子：
2
通讯作者：
N. Hirayama;A. Endo;K. Fujita;Y. Hasegawa;N. Hatano;H. Nakamura;R. Shirasaki;K. Yonemitsu
中科院分区：
文献类型：
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作者：
N. Hirayama;A. Endo;K. Fujita;Y. Hasegawa;N. Hatano;H. Nakamura;R. Shirasaki;K. Yonemitsu
研究了垂直磁场作用下二维电子气(2DEG)中直流电流感应的温度空间分布。我们利用一对非线性泊松方程(对于ϕ和T)，充分考虑了霍尔效应、能斯特效应、爱丁豪森效应和Righi-Leduc效应，数值计算了二维正方形区域内的静电势和温度的分布，该区域被绝缘绝热(顶部和底部)和等势等温(左和右)边界(ϕLeft<；ϕRight=Tright)包围。我们发现，在左下角附近，温度变得低于固定的边界温度，这与普遍的焦耳加热效应导致温度升高的天真预期相反。冷却归因于底部绝热边界的Ettinghausen效应，该效应将热量从底部边界抽走。为了保持绝热条件，在边界附近形成了向下的温度梯度，从而形成了冷却区，由此产生的热扩散补偿了由于埃丁豪森效应而产生的向上的热流。
We investigate the spatial distribution of temperature induced by a dc current in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field. We numerically calculate the distributions of the electrostatic potentialϕand the temperatureTin a 2DEG enclosed in a square area surrounded by insulated-adiabatic (top and bottom) and isopotential-isothermal (left and right) boundaries (withϕleft<ϕrightandTleft=Tright), using a pair of nonlinear Poisson equations (forϕandT) that fully take into account thermoelectric and thermomagnetic phenomena, including the Hall, Nernst, Ettingshausen, and Righi-Leduc effects. We find that, in the vicinity of the left-bottom corner, the temperature becomes lower than the fixed boundary temperature, contrary to the naive expectation that the temperature is raised by the prevalent Joule heating effect. The cooling is attributed to the Ettingshausen effect at the bottom adiabatic boundary, which pumps up the heat away from the bottom boundary. In order to keep the adiabatic condition, downward temperature gradient, hence the cooled area, is developed near the boundary, with the resulting thermal diffusion compensating the upward heat current due to the Ettingshausen effect.