(a) Spin-polarized thermovoltages (Vc) measured in a tunneling junction formed between a STM tip and Co nano-islands using SP-STVthM. The Vc is overlaid as a color map onto the 3D topography STM image, where Co nano-islands are grown on a Cu(111) surface on which Friedel oscillations are clearly seen.
(b) Vc histogram of a Co nano-island and surrounding Cu.
(c) Line profiles across the Co island in (b). The height (z) profile shows a 2 ML thick island with distinct contrast on and off the island in the simultaneously acquired Vc profile
(b) Vc histogram of a Co nano-island and surrounding Cu.
(c) Line profiles across the Co island in (b). The height (z) profile shows a 2 ML thick island with distinct contrast on and off the island in the simultaneously acquired Vc profile
Scientific Achievement
Spin-polarized scanning tunneling thermovoltage microscopy (SP-STVthM) is developed to resolve spin-dependent thermoelectric power with nanometer resolution.
Significance and Impact
This work establishes a new approach to spatially resolving the spin-Seebeck effect, allowing for the evaluation of confinement effects and local inhomogeneities in spin-heat interactions, which are important for miniaturized device applications.
Research Details
- SP-STVthM detects spin-dependent thermovoltages in a tunneling junction formed by a sample surface and a ferromagnetic STM tip.
- First-principles and model calculations quantitatively reproduce the measured thermally generated spin voltages, showing a distinct thermovoltage in spin-up and spin-down charge transport channels.
J. Park, F. Lüpke, J. Jiang, X.-G. Zhang, and A.-P. Li, "Spin-dependent thermoelectric power of nano-islands," Nano Letters (2020). DOI: 10.1021/acs.nanolett.0c00972
