Thermoelectric properties of a ferromagnet-superconductor hybrid junction: Role of interfacial Rashba spin-orbit interaction
Thermoelectric properties of a ferromagnet-superconductor hybrid junction: Role of interfacial Rashba spin-orbit interaction
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DOI：
10.1103/physrevb.96.115404
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发表时间：
2016-11
影响因子：
3.7
通讯作者：
Paramita Dutta;A. Saha;A. Jayannavar
中科院分区：
文献类型：
--
作者：
Paramita Dutta;A. Saha;A. Jayannavar
研究了具有Rashba自旋轨道相互作用和界面层δ函数势垒的铁磁-超导混合结构的热电性质。在铁磁体中，热导率随温度呈指数上升，表现为一个跨越温标，将热导率随极化强度的变化分为两个相反的行为，而界面Rashba自旋轨道场的引入则使热导率随Rashba场强度的变化呈现非单调性。我们采用散射矩阵的方法来确定所有可能的散射过程的振幅在界面上解释的热电性能的设备。我们研究了Seebeck效应，并表明当铁磁体的极化趋向于半金属极限时，可以实现更高的热电势。在有限势垒存在下，即使对于较低的极化，它也可以被增强。当存在界面Rashba自旋轨道相互作用时，在弱或中等的界面Rashba场下，Seebeck系数随势垒强度和极化强度的增加而增大。从应用的角度来看，我们计算的品质因数，并显示，$zT\sim 4-5$与更高的极化的铁磁体在不存在和存在的弱或中等Rashba自旋轨道相互作用沿着与标量势垒。
We investigate thermoelectric properties of a ferromagnet-superconductor hybrid structure with Rashba spin-orbit interaction and delta function potential barrier at the interfacial layer. The exponential rise of thermal conductance with temperature manifests a cross-over temperature scale separating two opposite behaviors of it with the change of polarization in the ferromagnet whereas the inclusion of interfacial Rashba spin-orbit field results in a non-monotonic behavior of it with the strength of Rashba field. We employ scattering matrix approach to determine the amplitudes of all the scattering processes possible at the interface to explain the thermoelectric properties of the device. We examine Seebeck effect and show that higher thermopower can be achieved when the polarization of the ferromagnet tends towards the half-metallic limit. It can be enhanced even for lower polarization in presence of the finite potential barrier. In presence of interfacial Rashba spin-orbit interaction, Seebeck coefficient rises with the increase of barrier strength and polarization at weak or moderate interfacial Rashba field. From the application perspective, we compute the figure of merit and show that $zT\sim 4-5$ with higher polarization of the ferromagnet both in absence and presence of weak or moderate Rashba spin-orbit interaction along with the scalar potential barrier.