Seminar: Magnetic Proximity Effects in Two-Dimensional Materials Igor Žutić
University at Buffalo
22/02/2019/ at 15:00h
IF - predavaonica u zgradi Mladen Paić

Proximity effects can transform a given material through its adjacent regions to become superconducting, magnetic, or topologically nontrivial [1]. 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 [2-4]. Bias-controlled spin polarization reversal in Co/h-BN/graphene [2] suggests that magnetic proximity effects may overcome the need for an applied magnetic field and a magnetization reversal to implement spin logic [5]. 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 [4]. Magnetic proximity-controlled TMD lasers may extend advantages of using spin-polarized carriers we demonstrated in lasers based on conventional semiconductors [6]. Combined magnetic and superconducting proximity effects could produce topological materials and realize elusive Majorana bounds states (MBS) for fault-tolerant quantum computing [7,8]. Exchanging (braiding) MBS yields a noncommutative phase, a sign of non-Abelian statistics and nonlocal degrees of freedom protected from local perturbations.

 

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