부산대학교 도서관

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. [ABSTRACT FROM AUTHOR]