Thermal Transport and Nonequilibrium Temperature Drop Across a Magnetic Tunnel Junction.
Thermal Transport and Nonequilibrium Temperature Drop Across a Magnetic Tunnel Junction.
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DOI：
10.1103/physrevlett.115.037203
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发表时间：
2015-03
影响因子：
8.6
通讯作者：
Jia Zhang;M. Bachman;M. Czerner;C. Heiliger
中科院分区：
文献类型：
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作者：
Jia Zhang;M. Bachman;M. Czerner;C. Heiliger
在自旋热电子领域，在当前的一些实验中，在纳米结构界面上施加温度梯度，观察到自旋相关的输运现象。这些实验的解释并不清楚，因为声子和电子都可能参与热输运。因此，在微观上，磁性纳米结构界面上的温度下降是如何产生的仍然是一个悬而未决的问题。我们针对发生隧道磁塞贝克效应的磁隧道结（MTJ）的情况回答了这个问题。我们的解释可以扩展到其他类型的纳米结构界面。我们明确计算声子和电子热传导跨Fe/MgO/Fe MTJs在从头开始的方法使用格林函数方法。此外，我们能够通过估计Fe引线中的电子-声子相互作用来计算Fe/MgO/Fe MTJ上的电子和声子温度分布。结果表明，在Fe-MgO界面处存在电子-声子温度不平衡。因此，可能需要对当前实验测量的解释进行修正。
In the field of spin caloritronics, spin-dependent transport phenomena are observed in a number of current experiments where a temperature gradient across a nanostructured interface is applied. The interpretation of these experiments is not clear as both phonons and electrons may contribute to thermal transport. Therefore, it still remains an open question how the temperature drop across a magnetic nanostructured interface arises microscopically. We answer this question for the case of a magnetic tunnel junction (MTJ) where the tunneling magneto-Seebeck effect occurs. Our explanation may be extended to other types of nanostructured interfaces. We explicitly calculate phonon and electron thermal conductance across Fe/MgO/Fe MTJs in an ab initio approach using a Green function method. Furthermore, we are able to calculate the electron and phonon temperature profile across the Fe/MgO/Fe MTJ by estimating the electron-phonon interaction in the Fe leads. Our results show that there is an electron-phonon temperature imbalance at the Fe-MgO interfaces. As a consequence, a revision of the interpretation of current experimental measurements may be necessary.