SKM 2021 – scientific programme
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SYSD: Symposium SKM Dissertation Prize 2021
SYSD 1: Presentations of the Finalists for the 2021 SKM Dissertation Prize
SYSD 1.3: Invited Talk
Monday, September 27, 2021, 10:55–11:20, Audimax 2
Attosecond-fast electron dynamics in graphene and graphene-based interfaces — •Christian Heide — Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen
Graphene, a two-dimensional material, is an ideal material to coherently drive electrons in a conducting material using strong light fields. In the band structure, when the electron is driven near the Dirac point - the point where the conduction and valence bands touch - the wave function of the electron can split into a superposition of the two band states. After half an optical cycle of about 1.3 femtoseconds (1 fs = 10−15s), these parts of the wave function meet again and interfere, producing a current flow within one femtosecond. Its amplitude and phase are not only sensitive to the waveform of the laser field, but also to the band structure and its topology, which makes this process interesting for ultrafast electronics and the study of solid-state properties.
Furthermore, graphene attached to a semiconductor forms a functional Schottky junction. We have shown that charge transfer across the interface occurs within 0.3 fs - the fastest known charge transfer between two solids. The reason for the short charge transfer time is the combination of the materials used: the atomically thin graphene with excited electrons directly at the interface and the extended semiconductor, which is ideally suited to receive the excited electrons.
Both results, the coherent control of electrons in an electrical conductor and the attosecond-fast charge transfer, are important steps towards light-field driven electronics, i.e. another direct link between photonics and electronics.