posted on 2022-01-28, 19:04authored byVictor
H. Guarochico-Moreira, Jose L. Sambricio, Khalid Omari, Christopher R. Anderson, Denis A. Bandurin, Jesus C. Toscano-Figueroa, Noel Natera-Cordero, Kenji Watanabe, Takashi Taniguchi, Irina V. Grigorieva, Ivan J. Vera-Marun
Spintronics
involves the development of low-dimensional electronic
systems with potential use in quantum-based computation. In graphene,
there has been significant progress in improving spin transport characteristics
by encapsulation and reducing impurities, but the influence of standard
two-dimensional (2D) tunnel contacts, via pinholes and doping of the
graphene channel, remains difficult to eliminate. Here, we report
the observation of spin injection and tunable spin signal in fully
encapsulated graphene, enabled by van der Waals heterostructures with
one-dimensional (1D) contacts. This architecture prevents significant
doping from the contacts, enabling high-quality graphene channels,
currently with mobilities up to 130 000 cm2 V–1 s–1 and spin diffusion lengths
approaching 20 μm. The nanoscale-wide 1D contacts allow spin
injection both at room and at low temperature, with the latter exhibiting
efficiency comparable with 2D tunnel contacts. At low temperature,
the spin signals can be enhanced by as much as an order of magnitude
by electrostatic gating, adding new functionality.