Dynamic Opening of a Gap in Dirac Surface States of the Thin-Film 3D Topological Insulator Bi2Se3 Driven by the Dynamic Rashba Effect

Abstract

Optical control of Dirac surface states (SS) in topological insulators (TI) remains one of the most challenging problems governing their potential applications in novel electronic and spintronic devices. Here, using visible-range transient absorption spectroscopy exploiting ~340 nm (~3.65 eV) pumping, we provide evidence for dynamic opening of a gap in Dirac SS of the thin-film 3D TI Bi2Se3, which has been induced by the dynamic Rashba effect occurring in the film bulk with increasing optical pumping power (photoexcited carrier density). The observed effect appears through the transient absorption band associated with inverse-bremsstrahlung-type free carrier absorption in the gapped Dirac SS. We have also recognized experimental signatures of the existence of the higher energy Dirac SS in the 3D TI Bi2Se3 (in addition to those known as SS1 and SS2) with energies of ~2.7 and ~3.9 eV (SS3 and SS4). It is evidenced that the dynamic gap opening has the same effect on the Dirac SS occurring at any energy.

References in corpus (19)

• Topological Insulators
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Crossover of Three-Dimensional Topological Insulator of Bi2Se3 to the Two-Dimensional Limit
• Observation of Floquet-Bloch states on the surface of a topological insulator
• A topological insulator surface under strong Coulomb, magnetic and disorder perturbations
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Bulk Fermi surface coexistence with Dirac surface state in Bi${}_2$Se${}_3$: a comparison of photoemission and Shubnikov-de Haas measurements
• Large tuneable Rashba spin splitting of a two-dimensional electron gas in Bi2Se3
• Spin polarization of the quantum spin Hall edge states
• Emergent quantum confinement at topological insulator surfaces
• Ultra-low carrier concentration and surface dominant transport in Sb-doped Bi2Se3 topological insulator nanoribbons
• Direct Optical Coupling to an Unoccupied Dirac Surface State in the Topological Insulator Bi${}_2$Se${}_3$
• Ultrafast carrier dynamics in thin-films of the topological insulator Bi2Se3
• Out-of-plane spin polarization from in-plane electric and magnetic fields
• Effect of carrier recombination on ultrafast carrier dynamics in thin films of the topological insulator Bi2Se3
• All-optical nonequilibrium pathway to stabilizing magnetic Weyl semimetals in pyrochlore iridates
• Clarifying ultrafast carrier dynamics in ultrathin films of the topological insulator Bi2Se3 using transient absorption spectroscopy
• Unconventional transformation of spin Dirac phase across a topological quantum phase transition
• Nonlinear Optical Observation of Coherent Acoustic Dirac Plasmons in Thin-Film Topological Insulators

Cited by in corpus (4)

• Coherent surface-to-bulk vibrational coupling in the 2D topologically trivial insulator Bi2Se3 monitored by ultrafast transient absorption spectroscopy
• Multiphoton-pumped UV-Vis transient absorption spectroscopy of 2D materials: basic concepts and recent applications
• Ultrafast transient absorption spectroscopy of 2D semiconductors: a review
• Two-photon IR pumped UV-Vis transient absorption spectroscopy of Dirac fermions in the 2D and 3D topological insulator Bi2Se3