Exploring the Electronic Structure and Chemical Homogeneity of Individual Bi₂Te₃ Nanowires by Nano-Angle-Resolved Photoemission Spectroscopy

Abstract

Due to their high surface-to-volume ratio, cylindrical Bi2Te3 nanowires are employed as model systems to investigate the chemistry and the unique conductive surface states of topological insulator nanomaterials. We report on nanoangle-resolved photoemission spectroscopy (nano-ARPES) characterization of individual cylindrical Bi2Te3 nanowires with a diameter of 100 nm. The nanowires are synthesized by electrochemical deposition inside channels of ion-track etched polymer membranes. Core level spectra recorded with submicron resolution indicate a homogeneous chemical composition along individual nanowires, while nano-ARPES intensity maps reveal the valence band structure at the single nanowire level. First-principles electronic structure calculations for chosen crystallographic orientations are in good agreement with those revealed by nano-ARPES. The successful application of nano-ARPES on single one-dimensional nanostructures constitutes a new avenue to achieve a better understanding of the electronic structure of topological insulator nanomaterials.

Magnetotransport signatures of three-dimensional topological insulator nanostructures

“…Furthermore, these surface states have been probed directly, using, e.g., nano-ARPES or Kelvin probe microscopy techniques. 28,30,31 There is a solid understanding of uniaxial 3D TI nanowire (or ribbon) surface states in the presence of a magnetic field and different approaches have been introduced to model this system, e.g., effective and continuous (Dirac-like) surface models, [32][33][34][35] surface and bulk lattice models 36,37 and a Luttinger liquid description in the 1D limit. 38 Here, we extend these efforts to other 3D TI nanostructures, such as kinks or junctions, which have been proposed as the basic building blocks of 3D TI nanowire circuits for Majorana-based quantum information processing, for example.…”

High-Throughput Screening and Automated Processing toward Novel Topological Insulators

“…For the band structure calculations, the k-paths were selected based on the lattice symmetry . The semi-infinite surface states were obtained using the algorithm proposed by Sancho et al based on the WFs, and the different surface states were calculated by folding the unit cell with the desired surfaces . The symmetry-adapted WFs were obtained using the full-potential local orbital (FPLO) code. − …”

“…44 The semi-infinite surface states were obtained using the algorithm proposed by Sancho et al 36 based on the WFs, 45 and the different surface states were calculated by folding the unit cell with the desired surfaces. 46 The symmetry-adapted WFs were obtained using the full-potential local orbital (FPLO) code. 47−49 To determine the Z 2 topological invariant for the compounds with inversion symmetry considered in the current work, the parities of the valence bands at eight TRIMs were calculated.…”

Quantum Transport in Nanostructures of 3D Topological Insulators

“…The electrochemical deposition of 3D TI NWs within ion‐track etched polymer membranes might be in this view a suitable growth method. [ 29–31 ] The principle of such a growth is shown in Figure 2 together with some TEM pictures of NWs grown by this technique. NWs of Bi 2 Te 3 with diameters ranging from 25 to 120 nm could be obtained.…”