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Is there a rashba effect in graphene on 3d ferromagnets?
O Rader1, A Varykhalov, J Sánchez-Barriga
1Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.
Physical Review Letters
|March 5, 2009
Summary
This study investigated graphene spintronics, finding no evidence of a Rashba effect on nickel or cobalt. The research indicates that reported effects are not due to spin-orbit coupling or electron spin interactions.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spintronics
Background:
- Graphene is a promising material for spintronics applications.
- Previous reports suggested a magnetization-dependent Rashba effect in graphene on Ni(111).
Purpose of the Study:
- To investigate the preconditions for a Rashba effect in graphene on magnetic substrates (Ni and Co).
- To determine if spin polarization, exchange splitting, or Rashba-type spin-orbit splitting are present.
Main Methods:
- Utilized spin- and angle-resolved photoelectron spectroscopy.
- Examined graphene grown on Ni(111) and Co(111) substrates.
- Focused on normal emission geometry and off-normal measurements.
Main Results:
- No considerable spin polarization or exchange splitting of graphene pi states was observed.
- No significant Rashba-type spin-orbit splitting was detected off normal emission.
- The preconditions for the reported Rashba effect were not met.
Conclusions:
- The previously reported effect in graphene on Ni(111) is not Rashba-type.
- The observed phenomena are not attributable to spin-orbit coupling or electron spin interactions.
- Graphene on these magnetic substrates does not exhibit the expected spintronic behavior.
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