Electronic spin transport and spin precession in single graphene layers at room temperature

By N. Tombros, C. Jozsa, M. Popinciuc, H. Jonkman, B. V. van Wees. Nature, 2007

2,083 citations recorded by the source corpus.

Electronic transport in single or a few layers of graphene is the subject of intense interest at present. The specific band structure of graphene, with its unique valley structure and Dirac neutrality point separating hole states from electron states, has led to the observation of new electronic transport phenomena such as anomalously quantized Hall effects, absence of weak localization and the existence of a minimum conductivity. In addition to dissipative transport, supercurrent transport has also been observed. Graphene might also be a promising material for spintronics and related applications, such as the realization of spin qubits, owing to the low intrinsic spin orbit interaction, as well as the low hyperfine interaction of the electron spins with the carbon nuclei. Here we report the observation of spin transport, as well as Larmor spin precession, over micrometre-scale distances in single graphene layers. The ‘non-local’ spin valve geometry was used in these experiments, employing four-terminal contact geometries with ferromagnetic cobalt electrodes making contact with the graphene sheet through a thin oxide layer. We observe clear bipolar (changing from positive to negative sign) spin signals that reflect the magnetization direction of all four electrodes, indicating that spin coherence extends underneath all of the contacts. No significant changes in the spin signals occur between 4.2 K, 77 K and room temperature. We extract a spin relaxation length between 1.5 and 2 μm at room temperature, only weakly dependent on charge density. The spin polarization of the ferromagnetic contacts is calculated from the measurements to be around ten per cent.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/dc7ebd33a8083e7ac518d2c98b26e5ecbc3d4a70

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Citations in the corpus

Long-distance transport of magnon spin information in a magnetic insulator at room temperature (2015, background): “The solution to equation (3) is of the form nm(x)=aexp(−x/λ)+bexp(x/λ), and from the boundary conditions we find for the magnon diffusion current density jm=−D(dnm/dx) at the detector: jm(x=d)=−2D n0 λ exp(d/λ) 1−exp(2d/λ) (4)”
Controllable growth of 1–7 layers of graphene by chemical vapour deposition (2014, background): “Graphene, a novel two-dimensional monolayer material consisting of a hexagonal crystal structure of SP(2)-bonded carbon atoms, is gaining much attention due to its particular structure and great potential for a wide range of applications [1-4].”
Origin and magnitude of 'designer' spin-orbit interaction in graphene on semiconducting transition metal dichalcogenides (2016, background): “For instance, devices can be realized by employing ferromagnetic electrical contacts that enable injection and detection of spins in graphene [19, 59].”
Electronic transport in two-dimensional graphene (2010, background): “…by exploiting its spin Cho et al. (2007); Han et al. (2009); Hill et al. (2006); Huertas-Hernando et al. (2006, 2009); Józsa et al. (2009); Tombros et al. (2007) or valley Rycerz et al. (2007b) degeneracy or by patterning gates with a periodic super-potential (Brey and Fertig, 2009a;…”
The electronic properties of graphene (2007, background): “The amazingtransport properties of graphene allow for their use ina plethora of appli ations ranging from single mole uledete tion (S hedin et al., 2007; Wehling et al., 2007)to spin inje tion (Cho et al., 2007; Hill et al., 2007;Ohishi et al., 2007; Tombros et al., 2007).”
Carbon-based electronics. (2007, background): “Spin transport and spin precession over micrometre-scale distances have also been demonstrated in single graphene sheets at room temperatur”