Spatial Control of Charge Doping in n-Type Topological Insulators

Sakamoto, Kazuyuki; Ishikawa, Hirotaka; Wake, Takashi; Ishimoto, Chie; Fujii, Jun; Bentmann, Hendrik; Ohtaka, Minoru; Kuroda, Kenta; Inoue, Natsu; Hattori, Takefumi; Miyamachi, Toshio; Komori, Fumio; Yamamoto, Ichiro; Fan, C.; Krüger, Péter; Ōta, Hiroshi; Matsui, Fumihiko; Reinert, F.; Ávila, J.; Asensio, M. C.

doi:10.1021/acs.nanolett.1c01100

Cited by 10 publications

(3 citation statements)

References 37 publications

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“…Exposure to ambient environments has been shown to alter measured ARPES spectra and the surface composition in Bi 2 Se 3 [31][32][33][34]. The topological surfaces states can be modified by forming 2D quantum well states in ambient conditions [32], and can present band-bending and controlled charge-doping after dosing H 2 O [31] and UV irradiation [35]. In most cases, the robust topological surface states are still present in Bi 2 Se 3 despite air exposure and oxidation [32,36].…”

Section: Discussionmentioning

confidence: 99%

Copper migration and surface oxidation of CuxBi2Se3 in ambient pressure environments

Gross¹,

Falling²,

Staab³

et al. 2022

J. Phys. Mater.

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Chemical modifications such as intercalation can be used to modify surface properties or to further functionalize the surface states of topological insulators. Using ambient pressure X-ray photoelectron spectroscopy, we report copper migration in Cux Bi2Se3, which occurs on a timescale of hours to days after initial surface cleaving. The increase in near-surface copper proceeds along with the oxidation of the sample surface and large changes in the selenium content. These complex changes are further modelled with core-level spectroscopy simulations, which suggest a composition gradient near the surface which develops with oxygen exposure. Our results shed light on a new phenomenon that must be considered for intercalated topological insulators—and intercalated materials in general—that surface chemical composition can change when specimens are exposed to ambient conditions.

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Section: Discussionmentioning

confidence: 99%

Copper migration and surface oxidation of CuxBi2Se3 in ambient pressure environments

Gross¹,

Falling²,

Staab³

et al. 2022

J. Phys. Mater.

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show abstract

“…On the other hand, the role of the surface atomic structure in TSSs is regarded as rather unimportant because of the robustness. Some theoretical and experimental studies reported modification of TSSs by surface treatments, such as surface oxidization 4 , chemical or photochemical ageing 5 , 6 , and a small interlayer rotation forming a moiré modulation on the surface 7 . However, such previous works were focused on how to perturb the pristine TSS.…”

Section: Introductionmentioning

confidence: 99%

Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB6(001)

et al. 2022

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The topology and spin-orbital polarization of two-dimensional (2D) surface electronic states have been extensively studied in this decade. One major interest in them is their close relationship with the parities of the bulk (3D) electronic states. In this context, the surface is often regarded as a simple truncation of the bulk crystal. Here we show breakdown of the bulk-related in-plane rotation symmetry in the topological surface states (TSSs) of the Kondo insulator SmB6. Angle-resolved photoelectron spectroscopy (ARPES) performed on the vicinal SmB6(001)-p(2 × 2) surface showed that TSSs are anisotropic and that the Fermi contour lacks the fourfold rotation symmetry maintained in the bulk. This result emphasizes the important role of the surface atomic structure even in TSSs. Moreover, it suggests that the engineering of surface atomic structure could provide a new pathway to tailor various properties among TSSs, such as anisotropic surface conductivity, nesting of surface Fermi contours, or the number and position of van Hove singularities in 2D reciprocal space.

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“…On the other hand, the role of the surface atomic structure in TSSs is regarded as rather unimportant because of the robustness. Some theoretical and experimental studies reported modification of TSSs by surface treatments, such as surface oxidization [4], chemical or photochemical ageing [5,6], and a small interlayer rotation forming a moiré modulation on the surface [7]. However, such previous works were focused on how to perturb the pristine TSS.…”

mentioning

confidence: 99%

Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB$_6$(001)

Ohtsubo¹,

Toru²,

Nakamura³

et al. 2022

Preprint

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The topology and spin-orbital polarization of two-dimensional (2D) surface electronic states have been extensively studied in this decade. One major interest in them is their close relationship with the parities of the bulk (3D) electronic states. In this context, the surface is often regarded as a simple truncation of the bulk crystal. Here we show breakdown of the bulk-related in-plane rotation symmetry in the topological surface states of the Kondo insulator SmB 6 . Angle-resolved photoelectron spectroscopy (ARPES) performed on the vicinal SmB 6 (001)-p(2×2) surface showed that the topological surface states are anisotropic and that the Fermi contour lacks the fourfold rotation symmetry maintained in the bulk. This result emphasizes the important role of the surface atomic structure even in the topological surface electronic states. Moreover, the characteristic anisotropy of the SmB 6 (001) surface states provides a new pathway to interpret the exotic electronic phenomena in the small Kondo gap of SmB 6 , whose origin, from the 3D bulk or 2D surface, is still controversial.

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Spatial Control of Charge Doping in n-Type Topological Insulators

Cited by 10 publications

References 37 publications

Copper migration and surface oxidation of CuxBi2Se3 in ambient pressure environments

Copper migration and surface oxidation of CuxBi2Se3 in ambient pressure environments

Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB6(001)

Breakdown of bulk-projected isotropy in surface electronic states of topological Kondo insulator SmB$_6$(001)

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