Observation of optical absorption correlated with surface state of topological insulator

Abstract

We performed broadband optical transmission measurements of Bi2Se3 and In-doped Bi(1-x)In(x)2Se3 thin films, where in the latter the spin-orbit coupling (SOC) strength can be tuned by introducing In. Drude and interband transitions exhibit In-dependent changes that are consistent with evolution from metallic (x=0) to insulating (x=1) nature of the end compounds. Most notably, an optical absorption peak located at hw=1eV in Bi2Se3 is completely quenched at x=0.06, the critical concentration where the phase transition from TI into non-TI takes place. For this x, the surface state (SS) is vanished from the band structure as well. The correlation between the 1eV optical peak and the SS in the x-dependences suggests that the peak is associated with the SS. We further show that when Bi2Se3 is electrically gated, the 1eV-peak becomes stronger(weaker) when electron is depleted from (accumulated into) the SS. These observations combined together demonstrate that under the hw=1eV illumination electron is excited from a bulk band into the topological surface band of Bi2Se3. The optical population of surface band is of significant importance not only for fundamental study but also for TI-based optoelectronic device application.

arXiv comment9 pages, 5 figures

References in corpus (28)

• Topological Insulators
• Topological insulators and superconductors
• Topological Insulators in Three Dimensions
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Kramers-Kronig constrained variational analysis of optical spectra
• Control over topological insulator photocurrents with light polarization
• Bulk Fermi surface coexistence with Dirac surface state in Bi${}_2$Se${}_3$: a comparison of photoemission and Shubnikov-de Haas measurements
• Observation of topological order in a Superconducting doped topological insulator (based on the Bi2Se3 class)
• Observation of Dirac plasmons in a topological insulator
• A sudden collapse in the transport lifetime across the topological phase transition in $(B{i}_{1-x}I{n}_x{)}_{2}S{e}_3$
• THz response and colossal Kerr rotation from the surface states of the topological insulator Bi${}_2$Se${}_3$
• Optical characterization of Bi${}_2$Se${}_3$ in a magnetic field: infrared evidence for magnetoelectric coupling in a topological insulator material
• Electronic Structure of the Topological Insulator Bi2Se3 Using Angle-Resolved Photoemission Spectroscopy: Evidence for a Nearly Full Surface Spin Polarization
• Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface
• Topological-Metal to Band-Insulator Transition in (Bi1-xInx)2Se3 Thin Films
• Direct Optical Coupling to an Unoccupied Dirac Surface State in the Topological Insulator Bi${}_2$Se${}_3$
• Evidence for a direct band gap in the topological insulator Bi2Se3 from theory and experiment
• Optical conductivity of Bismuth-based topological insulator
• Gate tunable optical absorption and band structure of twisted bilayer graphene
• Finite-size and composition-driven topological phase transition in (Bi${}_{1-x}$In${}_x$)${}_2$Se${}_3$ thin films
• Robust topological surface states of Bi2Se3 thin films on amorphous SiO2/Si substrate and a large ambipolar gating effect
• Gate-Variable Mid-Infrared Optical Transitions in a $(B{i}_{1-x}S{b}_x{)}_{2}T{e}_3$ Topological Insulator
• Interband absorption edge in topological insulators Bi${}_2$(Te${}_{1-x}$Se${}_x$)${}_3$
• Infrared spectroscopic study of carrier scattering in gated CVD graphene
• Infrared study of carrier scattering mechanism in ion-gated graphene
• The hole Fermi surface in Bi${}_2$Se${}_3$ probed by quantum oscillations