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Onderzoeksoutput per jaar
M. Gurram*, S. Omar, S. Zihlmann, P. Makk, Q. C. Li, Y. F. Zhang, C. Schonenberger, B. J. van Wees
Onderzoeksoutput › Academic › peer review
We study room-temperature spin transport in graphene devices encapsulated between a layer-by-layer-stacked two-layer-thick chemical vapor deposition (CVD) grown hexagonal boron nitride (hBN) tunnel barrier, and a few-layer-thick exfoliated-hBN substrate. We find mobilities and spin-relaxation times comparable to that of SiO2 substrate-based graphene devices, and we obtain a similar order of magnitude of spin relaxation rates for both the Elliott-Yafet and D'Yakonov-Perel' mechanisms. The behavior of ferromagnet/two-layer-CVDhBN/ graphene/hBN contacts ranges from transparent to tunneling due to inhomogeneities in the CVD-hBN barriers. Surprisingly, we find both positive and negative spin polarizations for high-resistance two-layer-CVD-hBN barrier contacts with respect to the low-resistance contacts. Furthermore, we find that the differential spininjection polarization of the high-resistance contacts can be modulated by dc bias from -0.3 to + 0.3 V with no change in its sign, while its magnitude increases at higher negative bias. These features point to the distinctive spin-injection nature of the two-layer-CVD-hBN compared to the bilayer-exfoliated-hBN tunnel barriers.
Originele taal-2 | English |
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Artikelnummer | 045411 |
Aantal pagina's | 8 |
Tijdschrift | Physical Review. B: Condensed Matter and Materials Physics |
Volume | 97 |
Nummer van het tijdschrift | 4 |
DOI's | |
Status | Published - 9-jan.-2018 |
Onderzoeksoutput › Academic › peer review
Gurram, M. (Speaker)
Activiteit: Professional or public presentation › Professional