Correlation between spin transport signal and Heusler/semiconductor interface quality in lateral spin-valve devices
| Autor: | Demie Kepaptsoglou, Vlado K. Lazarov, Kohei Hamaya, Balati Kuerbanjiang, Gavin R. Bell, Y. Fujita, Shinya Yamada, P. J. Hasnip, Michihiro Yamada, Ana M. Sanchez, Arsham Ghasemi, Kentarou Sawano |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Spin polarization Condensed matter physics business.industry Fermi level Spin valve 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Atomic units Condensed Matter::Materials Science symbols.namesake Semiconductor 0103 physical sciences Scanning transmission electron microscopy symbols Spin diffusion 010306 general physics 0210 nano-technology business Spectroscopy |
| Zdroj: | Physical Review B. 98 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.98.115304 |
| Popis: | We show direct evidence for the impact of Heusler/semiconductor interfaces atomic structure on the spin transport signals in semiconductor-based lateral spin-valve (LSV) devices. Based on atomic scale Z-contrast scanning transmission electron microscopy and energy dispersive x-ray spectroscopy we show that atomic order/disorder of ${\mathrm{Co}}_{2}{\mathrm{FeAl}}_{0.5}{\mathrm{Si}}_{0.5}$ (CFAS)/$n$-Ge LSV devices is critical for the spin injection in Ge. By conducting a postannealing of the LSV devices, we find 90% decrease in the spin signal while there is no difference in the electrical properties of the $\mathrm{CFAS}\text{/}n$-Ge contacts and in the spin diffusion length of the $n$-Ge layer. We show that the reduction in the spin signals after annealing is attributed to the presence of intermixing phases at the Heusler/semiconductor interface. First-principles calculations show how that intermixed interface region has drastically reduced spin polarization at the Fermi level, which is the main cause for the significant decrease of the spin signal in the annealed devices above $300{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. |
| Databáze: | OpenAIRE |
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