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Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au
E C T O'Farrell1, J Y Tan1, Y Yeo1
1Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore and Department of Physics, National University of Singapore, Singapore 117542, Singapore.
Physical Review Letters
|August 27, 2016
Summary
We created a 2D gold layer within a graphene and boron nitride heterostructure. This structure exhibits spin splitting and magnetic properties, persisting near room temperature.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Van der Waals heterostructures offer tunable electronic properties.
- Graphene and hexagonal boron nitride are key 2D materials for advanced electronics.
- Interfacial engineering is crucial for novel quantum phenomena.
Purpose of the Study:
- To investigate the electronic and magnetic properties of 2D gold intercalated in a graphene/hexagonal boron nitride heterostructure.
- To explore the effects of interfacial charge transfer and magnetic fields on the electronic band structure.
- To characterize the observed magnetoresistance and anomalous Hall effect.
Main Methods:
- Fabrication of van der Waals heterostructures with encapsulated 2D gold.
- Current annealing for interfacial charge redistribution and band structure analysis.
- Application of in-plane and displacement magnetic fields to probe spin properties.
- Measurement of magnetoresistance and anomalous Hall effect.
Main Results:
- Formation of a 2D gold layer at the interface, inducing graphene band structure splitting.
- Observation of in-plane spin polarization characteristic of Rashba interaction (~25 meV).
- Enhancement of band splitting by an applied displacement field.
- Giant negative magnetoresistance (up to 75%) and field-induced anomalous Hall effect below 1 T.
- Evidence of magnetic moment in hybridized gold and proximity to a collective magnetic phase.
Conclusions:
- The intercalated 2D gold layer significantly modifies the electronic and magnetic properties of the graphene heterostructure.
- The observed phenomena, including spin splitting and magnetoresistance, are attributed to interfacial effects and the magnetic nature of the hybridized gold.
- These findings suggest potential for novel spintronic and magnetic devices operating near room temperature.
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