Unoccupied Topological States on Bismuth Chalcogenides

Abstract

The unoccupied part of the band structure of topological insulators Bi${}_2$Te${}_x$Se${}_{3-x}$ ($x=0,2,3$) is studied by angle-resolved two-photon photoemission and density functional theory. For all surfaces linearly-dispersing surface states are found at the center of the surface Brillouin zone at energies around 1.3 eV above the Fermi level. Theoretical analysis shows that this feature appears in a spin-orbit-interaction induced and inverted local energy gap. This inversion is insensitive to variation of electronic and structural parameters in Bi${}_2$Se${}_3$ and Bi${}_2$Te${}_2$Se. In Bi${}_2$Te${}_3$ small structural variations can change the character of the local energy gap depending on which an unoccupied Dirac state does or does not exist. Circular dichroism measurements confirm the expected spin texture. From these findings we assign the observed state to an unoccupied topological surface state.

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Cited by in corpus (27)

• Colloquium: Topological Band Theory
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• Magnetic proximity effect at the 3D topological insulator/magnetic insulator interface
• Direct Optical Coupling to an Unoccupied Dirac Surface State in the Topological Insulator Bi${}_2$Se${}_3$
• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Tuning a Schottky barrier in a photoexcited topological insulator with transient Dirac cone electron-hole asymmetry
• Spin-Polarized Surface Resonances Accompanying Topological Surface State Formation
• Ultrafast Electron Dynamics in the Topological Insulator Bi2Se3 Studied by Time-Resolved Photoemission Spectroscopy
• Band resolved imaging of photocurrent in a topological insulator
• Surface vibrational modes of the topological insulator Bi${}_2$Se${}_3$ observed by Raman spectroscopy
• Effect of dynamical spectral weight redistribution on effective interactions in time-resolved spectroscopy
• Theoretical Understanding of Photon Spectroscopies in Correlated Materials In and Out of Equilibrium
• Joule meets van der Waals: Mechanical dissipation via image potential states on a topological insulator surface
• Double Band Inversion in $\alpha$-Sn: Appearance of Topological Surface States and the Role of Orbital Composition
• Unoccupied topological surface state in Bi${}_2$Te${}_2$Se
• Coherent Dirac plasmons in topological insulators
• Ultrafast Evolution of Bulk, Surface and Surface Resonance States in Photoexcited Bi${}_2$Te${}_3$
• Edge states and topological properties of electrons on the bismuth on silicon surface with giant spin-orbit coupling
• Resonant magneto-optic Kerr effect in the magnetic topological insulator Cr:(Sb${}_x$,Bi${}_{1-x}$)${}_2$Te${}_3$
• Electronic and Vibrational Excitations on the Surface of the Three-Dimensional Topological Insulator Bi${}_2$Te${}_{3-x}$Se${}_x$ (x = 0, 2, 3)
• Probing Image Potential States on Topological Semimetal Antimony Surface
• Two-photon IR pumped UV-Vis transient absorption spectroscopy of Dirac fermions in the 2D and 3D topological insulator Bi2Se3
• Ab initio k.p theory of spin-momentum locking: Application to topological surface states
• Unoccupied Topological Surface State in MnBi${}_2$Te${}_4$
• Artificial Gauge Field and Quantum Spin Hall States in a Conventional Two-dimensional Electron Gas