Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 33: Transport: Topological Semimetals 2 (jointly with MA/TT)
DS 33.7: Vortrag
Mittwoch, 22. März 2017, 16:45–17:00, HSZ 204
Emergent Weyl nodes and Fermi arcs in a Floquet Weyl semimetal — •Leda Bucciantini1, Stithadi Roy1, Sota Kitamura2, and Takashi Oka1 — 1Max Planck Institute for Physics of Complex Systems, Germany — 2Tokyo University, Japan
When a Dirac semimetal is subject to a circularly polarized laser, it is predicted that the Dirac cone splits into two Weyl nodes and a nonequilibrium transient state called the Floquet Weyl semimetal is realized. We focus on the previously unexplored low frequency regime, where the upper and lower Dirac bands resonantly couples with each other through multi-photon processes, which is a realistic situation in solid state ultrafast pump-probe experiments. We find a series of new Weyl nodes emerging in pairs when the Floquet replica bands hybridize with each other. The nature of the Floquet Weyl semimetal with regard to the number, locations, and monopole charges of these Weyl nodes is highly tunable with the amplitude and frequency of the light. We derive an effective low energy theory using Brillouin-Wigner expansion and further regularize the theory on a cubic lattice. The monopole charges obtained from the low-energy Hamiltonian can be reconciled with the number of Fermi arcs on the lattice which we find numerically.