Ultrafast Energy- and Momentum-resolved Surface Dirac Photocurrents in the Topological Insulator Sb${}_2$Te${}_3$

Abstract

We present energy-momentum mapping of surface Dirac photocurrent in the topological insulator Sb${}_2$Te${}_3$ by means of time- and angle-resolved two-photon photoemission spectroscopy combined with polarization-variable mid-infrared pulse laser. It is demonstrated that the direct optical transition from the occupied to the unoccupied part of the surface Dirac-cone permits the linear and circular photogalvanic effect which thereby enables us to coherently control the surface electric-current by laser polarization. Moreover, the surface current mapping directly visualizes ultrafast current dynamics in the Dirac cone in the time domain. We unravel the ultrafast intraband relaxation dynamics of the inelastic scattering and momentum scattering separately. Our observations pave the pathway for coherent optical control over surface Dirac electrons in topological insulators.

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Cited by in corpus (12)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Band resolved imaging of photocurrent in a topological insulator
• Infrared/Terahertz Spectra of the Photogalvanic Effect in (Bi,Sb)Te based Three Dimensional Topological Insulators
• Tuning time and energy resolution in time-resolved photoemission spectroscopy with nonlinear crystals
• High-frequency nonlinear transport and photogalvanic effects in two-dimensional topological insulators
• A narrow bandwidth extreme ultra-violet light source for time- and angle-resolved photoemission spectroscopy
• Highly superlinear photogalvanic effects in (Bi${}_{0.3}$Sb${}_{0.7}$)${}_2$(Te${}_{0.1}$Se${}_{0.9}$)${}_3$: Probing 3D topological insulator surface states at room temperature
• Ultrafast Momentum-resolved Hot Electron Dynamics in the Two-dimensional Topological Insulator Bismuthene
• Lifetime and surface-to-bulk scattering off vacancies of the topological surface state in the three-dimensional strong topological insulators Bi2Te3 and Bi2Se3
• Ultrafast dynamics of photocurrents in surface states of 3D topological insulators
• Visualization of optical polarization transfer to photoelectron spin vector emitted from the spin-orbit coupled surface state
• Terahertz time-domain signatures of the inverse Edelstein effect in topological-insulator|ferromagnet heterostructures