Ultrafast spin polarization control of Dirac fermions in topological insulators

Abstract

Three-dimensional topological insulators (TIs) are characterized by spin-polarized Dirac-cone surface states that are protected from backscattering by time-reversal symmetry. Control of the spin polarization of topological surface states (TSSs) using femtosecond light pulses opens novel perspectives for the generation and manipulation of dissipationless surface spin currents on ultrafast timescales. Using time-, spin-, and angle-resolved spectroscopy, we directly monitor for the first time the ultrafast response of the spin polarization of photoexcited TSSs to circularly-polarized femtosecond pulses of infrared light. We achieve all-optical switching of the transient out-of-plane spin polarization, which relaxes in about 1.2 ps. Our observations establish the feasibility of ultrafast optical control of spin-polarized Dirac fermions in TIs and pave the way for novel optospintronic applications at ultimate speeds.

9 pages, 4 figures

References in corpus (10)

• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Ultrafast Optical Excitation of a Persistent Surface-State Population in the Topological Insulator Bi2Se3
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• Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3
• Spin Polarization of Photoelectrons from Topological Insulators
• Momentum resolved spin dynamics of bulk and surface excited states in the topological insulator $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{e}}_3$
• One-step theory of pump-probe photoemission
• Hot-carrier transport and spin relaxation on the surface of topological insulator

Cited by in corpus (25)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Helicity dependent photocurrent in electrically gated (Bi,Sb)_2Te_3 thin films
• Band resolved imaging of photocurrent in a topological insulator
• A first principles TDDFT framework for spin and time-resolved ARPES in periodic systems
• Surface Fermi arc connectivity in the type-II Weyl semimetal candidate WTe${}_2$
• Sub-picosecond spin dynamics of excited states in the topological insulator Bi${}_2$Te${}_3$
• Spin Hall photoconductance in a 3D topological insulator at room temperature
• Ultrafast Energy- and Momentum-resolved Surface Dirac Photocurrents in the Topological Insulator Sb${}_2$Te${}_3$
• Unveiling the hidden nematicity and spin subsystem in FeSe
• Spin-, time- and angle-resolved photoemission spectroscopy on WTe${}_2$
• Laser-induced persistent photovoltage on the surface of a ternary topological insulator at room temperature
• Advancing time- and angle-resolved photoemission spectroscopy: The role of ultrafast laser development
• Time-, spin-, and angle-resolved photoemission spectroscopy with a 1-MHz 10.7-eV pulse laser
• Coherent Dirac plasmons in topological insulators
• Impact of ultrafast transport on the high-energy states of a photoexcited topological insulator
• Role of matrix elements in the time-resolved photoemission signal
• Electrostatical formation of the Majorana quasiparticles in the quantum dot--nanoring structure
• Ultrafast Evolution of Bulk, Surface and Surface Resonance States in Photoexcited Bi${}_2$Te${}_3$
• Ultrafast Hidden Spin Polarization Dynamics of Bright and Dark Excitons in 2H-WSe${}_2$
• Investigation of structural and magneto-transport properties of PdTe2 single crystals
• Ultrafast dynamics of photocurrents in surface states of 3D topological insulators
• Attosecond Polarisation Modulation of X-ray Radiation in a Free Electron Laser
• One-step theory of two-photon photoemission
• Control of intervalley scattering in Bi${}_2$Te${}_3$ via temperature-dependent band renormalization
• Terahertz time-domain signatures of the inverse Edelstein effect in topological-insulator|ferromagnet heterostructures