Probing chiral electronic excitations in bilayer graphene by Raman scattering

Elisa Riccardi (1) , Oleksiy Kashuba (2) , Maximilien Cazayous (1) , Marie-Aude Measson (3, 1) , Alain Sacuto (1) , Yann Gallais (1)

1 MPQ (UMR_7162) - Laboratoire Matériaux et Phénomènes Quantiques
2 University of Würzburg
3 NEEL - MagSup - Magnétisme et Supraconductivité

We report a symmetry-resolved electronic Raman scattering (ERS) study of a back-gated bilayer graphene device. We show that the ERS continuum is dominated by interband chiral excitations of A2 symmetry and displays a characteristic Pauli-blocking behavior similar to the monolayer case. Crucially, we show that nonchiral excitations make a vanishing contribution to the Raman cross-section due to destructive interference effects in the Raman amplitude matrix elements. This is in marked contrast to the optical absorption measurements and opens interesting prospects for the use of Raman scattering as a selective probe for the detection of the chiral degrees of freedom in graphene, topological materials, and other two-dimensional crystals.

Domaines: Autre [cond-mat.other]

Elisa Riccardi, Oleksiy Kashuba, Maximilien Cazayous, Marie-Aude Measson, Alain Sacuto, et al.. Probing chiral electronic excitations in bilayer graphene by Raman scattering. Physical Review Materials, 2019, 3 (1), pp.014002. ⟨10.1103/PhysRevMaterials.3.014002⟩. ⟨hal-02415790⟩