Park Jewook, Lüpke Felix, Jiang Jun, Zhang Xiao-Guang, Li An-Ping
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6487, United States.
Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea.
Nano Lett. 2020 Jul 8;20(7):4910-4915. doi: 10.1021/acs.nanolett.0c00972. Epub 2020 Jun 4.
The Seebeck effect explains the generation of electric voltage as a result of a temperature gradient. Its efficiency, defined as the ratio of the generated electric voltage to the temperature difference, is sensitive to local inhomogeneities that alter the scattering rate and the density of the conduction electrons. Spin-polarized Seebeck tunneling generates a distinct thermovoltage in spin-up and spin-down charge transport channels, which, as a key to spin caloritronics, focuses on transport phenomena related to spin and heat. Here, we report spatially resolved measurement of the spin-dependent thermovoltage in a tunneling junction formed by ferromagnetic Co nanoislands and a Ni tip using spin-dependent scanning tunneling thermovoltage microscopy (SP-STVM). We resolve the nanoscale thermoelectric powers with respect to spin polarization, nanoisland size, stacking order of Co layers on a Cu substrate, and local sample heterogeneities. The observed thermally generated spin voltages are supported by first-principles and model calculations.
塞贝克效应解释了由于温度梯度而产生的电压。其效率定义为产生的电压与温度差的比值，对改变传导电子散射率和密度的局部不均匀性很敏感。自旋极化塞贝克隧穿在自旋向上和自旋向下的电荷传输通道中产生独特的热电压，作为自旋热电子学的关键，它关注与自旋和热相关的传输现象。在这里，我们报告了使用自旋相关扫描隧道热电压显微镜（SP-STVM）对由铁磁钴纳米岛和镍尖端形成的隧道结中自旋相关热电压的空间分辨测量。我们解析了关于自旋极化、纳米岛尺寸、铜衬底上钴层的堆叠顺序以及局部样品不均匀性的纳米级热电势。观察到的热产生自旋电压得到了第一性原理和模型计算的支持。
