Recovery of surface state bands after desorption of Te capping layer on (Bi_1−xSb_x)₂Te₃ ternary topological insulators

Geoffroy Kremer (1) , Kejing Zhu (2) , Thomas Pierron (1) , Vincent Fournee (1) , Julian Ledieu (1) , Stéphane Andrieu (1) , Bertrand Kierren (1) , Luc Moreau (1) , Daniel Malterre (1) , Ke He (2) , Qi-Kun Xue (2) , Yannick Fagot-Revurat (1) , Yuan Lu (1)

1 IJL - Institut Jean Lamour
2 THU - Tsinghua University [Beijing]

Te capping layer on topological insulator (TI) surface provides an efficient way for the protection of surface from oxidation. However, when using Te to protect the surface of (Bi_1−xSb_x)₂Te₃ ternary topological insulators, it is still unclear for the influence of Te on the surface chemical composition and the surface state bands after the procedure of capping and desorption of Te. Here, we have performed a systematic study of the surface morphology, crystallinity, chemical composition as well as the band structure of (Bi_1−xSb_x)₂Te₃ after the desorption of the Te capping layer. Our results confirm a good recovery of the surface state bands of the (Bi_1−xSb_x)₂Te₃ ternary topological insulators with different Bi and Sb compositions. The chemical composition of (Bi_1−xSb_x)₂Te₃ remains almost unchanged after the desorption of Te. This study proves that the Te capping layer works as a suitable protection for ternary (Bi_1−xSb_x)₂Te₃ TI layers, allowing for ex-situ transfer of TI samples in air. This opens the way for the development of metal/TI hybrid structures for advanced spintronic applications.

Mots clés: Topological insulator; Surface state bands; Dirac point; Angle resolved photoemission spectroscopy; Capping and desorption

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Geoffroy Kremer, Kejing Zhu, Thomas Pierron, Vincent Fournee, Julian Ledieu, et al.. Recovery of surface state bands after desorption of Te capping layer on (Bi_1−xSb_x)₂Te₃ ternary topological insulators. Journal of Physics D: Applied Physics, 2019, 52 (49), pp.494002. ⟨10.1088/1361-6463/ab3fc3⟩. ⟨hal-02999617⟩