Spin- and valley-coupled electronic states in monolayer WSe{sub 2} on bilayer graphene

Journal Article · Mon Aug 17 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4928658· OSTI ID:22489107

Sugawara, K.; Souma, S. ^[1]; Sato, T.; Tanaka, Y. ^[2]; Takahashi, T. ^[1]

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1. WPI Research Center, Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)
2. Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

We have fabricated a high-quality monolayer WSe{sub 2} film on bilayer graphene by epitaxial growth and revealed the electronic states by spin- and angle-resolved photoemission spectroscopy. We observed a direct energy gap at the Brillouin-zone corner in contrast to the indirect nature of gap in bulk WSe{sub 2}, which is attributed to the lack of interlayer interaction and the breaking of space-inversion symmetry in monolayer film. A giant spin splitting of ∼0.5 eV, which is the largest among known monolayer transition-metal dichalcogenides, is observed in the energy band around the zone corner. The present results suggest a high potential applicability of WSe{sub 2} to develop advanced devices based with the coupling of spin- and valley-degrees of freedom.

• OSTI ID: 22489107
• Journal Information: Applied Physics Letters, Vol. 107, Issue 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRILLOUIN ZONES
COUPLING
DEGREES OF FREEDOM
ENERGY GAP
EPITAXY
FILMS
GRAPHENE
LAYERS
PHOTOELECTRON SPECTROSCOPY
SPIN
SYMMETRY
TRANSITION ELEMENTS