Spin-dependent quantum interference in nonlocal graphene spin valves.
Up to date, all spin transport experiments on graphene were done in a semiclassical regime, disregarding quantum transport properties such as phase coherence and interference. Here we show that in a quantum coherent graphene nanostructure the nonlocal voltage is strongly modulated. Using nonlocal measurements, we separate the signal in spin-dependent and spin-independent contributions. We show that the spin-dependent contribution is about 2 orders of magnitude larger than the spin-independent one, when corrected for the finite polarization of the electrodes. The nonlocal spin signal is not only strongly modulated but also changes polarity as a function of the applied gate voltage. By locally tuning the carrier density in the constriction via a side gate electrode we show that the constriction plays a major role in this effect. Our results show the potential of quantum coherent graphene nanostructures for the use in future spintronic devices.
Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen , 9712 CP Groningen, The Netherlands.
M H D
MH
Guimarães
P J
PJ
Zomer
I J
IJ
Vera-Marun
B J
BJ
van Wees