Options
Comparative fermiology study of PbBi <inf>2</inf> Te <inf>4</inf> and SnBi <inf>2</inf> Te <inf>4</inf> 3D topological insulators
Journal
Journal of Materials Science: Materials in Electronics
ISSN
09574522
Date Issued
2022-04-01
Author(s)
Mal, Priyanath
Das, Bipul
Bera, G.
Turpu, G. R.
Tomy, C. V.
Das, Pradip
Abstract
A comparative study of electronic transport and Hall measurements of PbBi2Te4 and SnBi2Te4 single crystals are presented here. The phase coherence lengths at different temperatures are determined by fitting observed low-field weak antilocalization (WAL) effect with modified Hikami-Larkin-Nagaoka equation. Temperature dependence of phase coherence lengths are described in conjugation with electron–electron (e–e) and electron–phonon (e–p) interactions. The fitting parameters reveal e–e, e–p interactions that follow T- 1, T- 2.68 power law, respectively, for PbBi2Te4 single crystal, while for SnBi2Te4 single crystal e-e and e-p interactions obey T- 1 and T- 2.8 power law, respectively. These indicate the two-dimensional conducting channels are participating in WAL effect. Analysis of the high-field beat-like Shubnikov-de Haas (SdH) oscillations reveals the presence of topological surface states and an elongated band outside the surface states, the non-trivial nature of which is confirmed from the observed 12-shift in Landau levels fan diagram. Estimated lower effective mass from Lifshitz-Kosevich (LK) fit and higher mobility values determined from Dingle analysis confirm the surface origin of the SdH oscillations. Comparison of the effective mass, quantum scattering time, mean free path, mobility, and metallicity parameters for the carriers at the topological surface states determined from the SdH oscillations for both the compounds reflect the topological surface states in PbBi2Te4 are of superior quality over the topological surface states in SnBi2Te4. This is indeed the case as Pb with higher atomic weight is replaced for Sn in SnBi2Te4, which provides more spin-orbit coupling in the system.