Sputtering induced re-emergence of the topological surface state in Bi${}_2$Se${}_3$

Abstract

We study the fate of the surface states of Bi${}_2$Se${}_3$ under disorder with strength larger than the bulk gap, caused by neon sputtering and nonmagnetic adsorbates. We find that neon sputtering introduces strong but dilute defects, which can be modeled by a unitary impurity distribution, whereas adsorbates, such as water vapor or carbon monoxide, are best described by Gaussian disorder. Remarkably, these two disorder types have a dramatically different effect on the surface states. Our soft x-ray ARPES measurements combined with numerical simulations show that unitary surface disorder pushes the Dirac state to inward quintuplet layers, burying it below an insulating surface layer. As a consequence, the surface spectral function becomes weaker, but retains its quasiparticle peak. This is in contrast to Gaussian disorder, which smears out the quasiparticle peak completely. At the surface of Bi${}_2$Se${}_3$, the effects of Gaussian disorder can be reduced by removing surface adsorbates using neon sputtering, which, however, introduces unitary scatterers. Since unitary disorder has a weaker effect than Gaussian disorder, the ARPES signal of the Dirac surface state becomes sharper upon sputtering.

5+2 pages. 4 figures

References in corpus (18)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Classification of topological insulators and superconductors in three spatial dimensions
• 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
• Surface States of the Topological Insulator Bi_{1-x}Sb_x
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Emergent quantum confinement at topological insulator surfaces
• Topological delocalization of two-dimensional massless Dirac fermions
• Unexpected mass acquisition of Dirac fermions at the quantum phase transition of a topological insulator
• Transmission of topological surface states through surface barriers
• Direct Measurement of the Out-of-Plane Spin Texture in the Dirac Cone Surface State of a Topological Insulator
• Quantum criticality and minimal conductivity in graphene with long-range disorder
• Z2 topological term, the global anomaly, and the two-dimensional symplectic symmetry class of Anderson localization
• The fate of topological-insulator surface states under strong disorder
• Response of the topological surface state to surface disorder in TlBiSe${}_2$
• Helical Majorana surface states of strongly disordered topological superconductors with time-reversal symmetry
• `Holographic' treatment of surface disorder on a topological insulator

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