SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 75: Focus Session: Ultrafast Dynamics in Nanostructures I
O 75.7: Vortrag
Donnerstag, 30. März 2023, 12:30–12:45, GER 38
Spin current control by hybrid pulses — •Jyoti Krishna1, Sangeeta Sharma2, Julen Ibañez-Azpiroz1,3, and Sam Shallcross2 — 1Centro de Fisica de Materiales (CSIC-UPV/EHU), 20018, San Sebastian, Spain — 2Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A,12489 Berlin — 3Ikerbasque Foundation, 48013 Bilbao, Spain
Spin and valley indices represent the key quantum labels of quasiparticles in a wide class of two dimensional materials, and control over these degrees of freedom, the creation of valley and spin states as well as the generation of pure spin and valley currents, remains a central challenge in these fields. Here we show that hybrid femtoscond laser pulses combining optical frequency circularly polarized pulse and a terahertz frequency linearly polarized pulse, a so-called "hencomb" pulse, can generate currents, whose magnitude and direction can be precisely controlled by the THz envelope. We explore this effect both in bilayer graphene and the dichalocogenide WSe2, finding control over substantial currents that are nearly 100% pure valley and spin currents respectively. Employing a Wannier tight-binding method we then explore the creation of coherent photocurrents in the 2d magnets CrI3 and FGT, generalizing the role of the THz and optical pulses to "momentum guiding" and "excitation" components of hybrid laser pulses.
Funding was provided by the European Union’s Horizon 2020 research and innovation programme under the European Research Council (ERC) grant agreement No 946629.