Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 2: Ultrafast Electron Dynamics at Surfaces and Interfaces 1
O 2.7: Vortrag
Montag, 5. September 2022, 12:00–12:15, H3
tr-ARPES experiment with mid-infrared excitation for dynamical band structure engineering — •Leonard Weigl1, Niklas Hofmann1, Johannes Gradl1, Neeraj Mishra2,3, Stiven Forti2, Camilla Coletti2,3, and Isabella Gierz1 — 1Department of Physics, University of Regensburg, 93040 Regensburg, Germany — 2Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy — 3Graphene Labs, Istituto Italiano di Tecnologia, 16163 Genova, Italy
The band structure of a solid is mainly determined by the orbital overlap between neighboring atoms. Therefore, electronic properties are commonly controlled via the chemical composition that determines structural parameters such as bond angles and lengths. Recently, control of the effective orbital overlap has been achieved by periodic modulation of solids with strong mid-infrared (MIR) light fields. The ideal probe for investigating driving-induced band structure changes is time- and angle-resolved photoemission spectroscopy (tr-ARPES). We have built a tr-ARPES setup that combines a strong-field wavelength-tunable MIR pump source with extreme ultraviolet probe pulses providing access to the band structure of driven solids across the complete first Brillouin zone with sub 100meV energy and sub 250fs temporal resolution. We present first results on driven graphene, analyze the MIR pump-induced carrier dynamics, and discuss the possible formation of photon-dressed states. The excellent performance of the setup now paves the way for the future investigation of light-induced superconductivity as well as light-induced topological phase transitions.