Photo-electrons unveil topological transitions in graphene-like systems.
The topological structure of the wavefunctions of particles in periodic potentials is characterized by the Berry curvature Ωknwhose integral on the Brillouin zone is a topological invariant known as the Chern number. The bulk-boundary correspondence states that these numbers define the number of edge or surface topologically protected states. It is then of primary interest to find experimental techniques able to measure the Berry curvature. However, up to now, there are no spectroscopic experiments that proved to be capable to obtain information on Ωknto distinguish different topological structures of the bulk wavefunctions of semiconducting materials. Based on experimental results of the dipolar matrix elements for graphene, here we show that ARPES experiments with the appropriate x-ray energies and polarization can unambiguously detect changes of the Chern numbers in dynamically driven graphene and graphene-like materials opening new routes towards the experimental study of topological properties of condensed matter systems.
Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energa Atómica, 8400 Bariloche, Argentina.
Lucila
L
Peralta Gavensky
Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energa Atómica, 8400 Bariloche, Argentina.|Consejo Nacional de Investigaciones Cientficas y Técnicas (CONICET), Argentina.
Gonzalo
G
Usaj
Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energa Atómica, 8400 Bariloche, Argentina.|Consejo Nacional de Investigaciones Cientficas y Técnicas (CONICET), Argentina.
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CA
Balseiro