Résumé |
Proximity effects can transform a given material through its adjacent regions to become superconducting,
magnetic, or topologically nontrivial. In bulk materials, the sample size often greatly exceeds the
characteristic lengths of proximity effects allowing their neglect. However, in 2D materials such as graphene,
transition-metal dichalcogenides (TMDs) and 2D electron gas (2DEG), the situation is drastically different.
Even short-range magnetic proximity effects exceed their thickness and strongly modify spin transport and
optical properties. Experimental confirmation of our prediction for bias-controlled spin polarization reversal in
Co/hBN/graphene suggests that magnetic proximity effects may overcome the need for an applied magnetic
field and a magnetization reversal to implement spin logic. In TMDs, where robust excitons dominate their
optical response, magnetic proximity effects cannot be described by the single-particle description. We
predict a conversion between optically inactive and active excitons by rotating the magnetization of the
substrate. Combined magnetic and superconducting proximity effects could enable elusive Majorana bounds
states (MBS) for fault-tolerant quantum computing. Exchanging (braiding) MBS yields a noncommutative
phase, a sign of non-Abelian statistics and nonlocal degrees of freedom protected from local perturbations.
MBS could be manipulated and braided in proximity-induced superconductivity in a 2DEG with magnetic
textures from the fringing fields of magnetic multilayers.
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