Low Temperature Weak Anti-Localization Effect in the GeTe and SnTe Epitaxial Layers

A. Khaliq, P. Dziawa, R. Minikaev, M. Arciszewska, A. Avdonin, B. Brodowska, L. Kilański Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, PL-02668 Warsaw, Poland

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IV-VI semiconductors possess intriguing multifunctional characteristics, such as topological surface states, ferroelectricity at room temperature, and giant Rashba spin-splitting, giving them the potential for next-generation spintronic applications. In this work, we are presenting the epitaxially grown layers α-GeTe and SnTe, their structural and high field magnetotransport results. The crystal structure of α-GeTe preserves the rhombohedral symmetry (R3m) below T~720 K manifesting ferroelectric polarization, whereas SnTe holds the cubic symmetry (Fm-3m) above T~80 K. The results of the variable temperature in the range 4.3≤T≤300 K show a weakly dependent charge concentration, i.e., p(T)=0.1×1021 cm-3 for SnTe and p(T)=0.7×1021 cm-3 for α-GeTe layers. Likewise, the hole mobility μh(T) remains almost constant in the range 4.3≤T≤15 K and changes to a metallic-like behavior when T≥15 K. Furthermore, the high field magnetoresistance ρxx(B) graphs of SnTe layers, measured between -13≤B≤13 T, demonstrate a prominent weak anti-localization effect below T=3 K and when |B|≤0.3 T. However, the weak anti-localization effect disappears at T=4.2 K for both the α-GeTe and SnTe epitaxial layers. Similarly, the ρxx(B) graphs of α-GeTe show a small effect only at the lowest temperature measured T=1.6 K. The calculated prefactor value α=-14, obtained by fitting the Δσxx(B) graphs with the Hikami-Larkin-Nagaoka model, indicates the bulk transport system in SnTe.

DOI:10.12693/APhysPolA.142.657 topics: IV-VI semiconductors (SCs), weak anti-localization effect, bulk conductivity