title: Theory of Floquet band formation and local pseudospin textures in pump-probe photoemission of graphene.
abstract: Ultrafast materials science promises optical control of physical properties of solids. Continuous-wave circularly polarized laser driving was predicted to induce a light-matter coupled state with an energy gap and a quantum Hall effect, coined Floquet topological insulator. Whereas the envisioned Floquet topological insulator requires high-frequency pumping to obtain well-separated Floquet bands, a follow-up question regards the creation of Floquet-like states in graphene with realistic low-frequency laser pulses. Here we predict that short optical pulses attainable in experiments can lead to local spectral gaps and novel pseudospin textures in graphene. Pump-probe photoemission spectroscopy can track these states by measuring sizeable energy gaps and Floquet band formation on femtosecond time scales. Analysing band crossings and pseudospin textures near the Dirac points, we identify new states with optically induced nontrivial changes of sublattice mixing that leads to Berry curvature corrections of electrical transport and magnetization.
authors.affiliation: 1] Stanford Institute for Materials and Energy Sciences (SIMES), Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2] HISKP University of Bonn, Bonn 53115, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Sentef
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: M
authors.initials: M
authors.lastname: Claassen
authors.affiliation: Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Kemper
authors.affiliation: 1] Stanford Institute for Materials and Energy Sciences (SIMES), Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2] Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA.
authors.forename: B
authors.initials: B
authors.lastname: Moritz
authors.affiliation: Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Oka
authors.affiliation: Department of Physics, Georgetown University, Washington, DC 20057, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Freericks
authors.affiliation: 1] Stanford Institute for Materials and Energy Sciences (SIMES), Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA [2] Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: T P
authors.initials: TP
authors.lastname: Devereaux