Response of the topological surface state to surface disorder in TlBiSe₂

Abstract

Through a combination of experimental techniques we show that the topmost layer of the topological insulator TlBiSe 2 as prepared by cleavage is formed by irregularly shaped Tl islands at cryogenic temperatures and by mobile Tl atoms at room temperature. No trivial surface states are observed in photoemission at low temperatures, which suggests that these islands cannot be regarded as a clear surface termination. The topological surface state is, however, clearly resolved in photoemission experiments. This is interpreted as direct evidence of its topological self-protection and shows the robust nature of the Dirac cone-like surface state. Our results can also help explain the apparent mass acquisition in Sdoped TlBiSe 2 .

Role of surface termination in realizing well-isolated topological surface states within the bulk band gap inTlBiSe2andTlBiTe2

“…2(c), consistent with experimental observations. 32,33 This surface is nonpolar with an equal number of Tl + and Se − atoms, and since the bulk stoichiometry is unbroken i.e. N Tl = N Bi = 2 × N Se , similar to Bi 2 Se 3 and SnTe, charge neutrality is maintained throughout the system in this case.…”

Surface state conductivity in epitaxially grown Bi1−xSbx(111) films

“…For instance, epitaxial layers of Bi Te 2 3 grown on ( ) BaF 111 2 substrates reveal mobilities up to 4600 cm Vs 2 1 at 14 K [14]. Moreover, this technique is well suited to control the surface stoichiometry and morphology, thus avoiding problems of termination which may occur during the cleavage process of bulk materials as confirmed for TlBiSe 2 [15,16].…”

THE Tl4PbTe3-Tl9GdTe6-Tl9BiTe6 ISOPLETH SECTION OF THE Tl-Pb-Bi-Gd-Te SYSTEM

“…Heavy metal chalcogenides, multicomponent phases and composites based thereon are valuable functional materials [1][2][3]. In recent years, interest in complex thallium chalcogenides has increased due to topological insulators [4][5][6], Weyl semimetals [6] and thermoelectric materials with anomalously low thermal conductivity [8][9][10]. Some of these compounds have photoconductivity and are promising for use as detectors of γ and X-ray radiation [11,12].…”