Thermal reliability and spin Hall angle of highly textured and epitaxial Bi_0.9Sb_0.1(012) topological insulator

Abstract In this study, we examine the impact of various seed layer materials that facilitate the growth of highly textured or epitaxial topological insulator Bi 0.9 Sb 0.1 (012) on Si/SiOx substrates. We found that cubic-textured (100) or tetragonal (001) seed layers facilitate the epitaxial growth of undoped Bi 1− x Sb x (012) with more square surface, while seed layers composed of (111) polycrystalline or, alternatively, nanocrystalline or amorphous materials are suitable for growth of highly textured Bi 1− x Sb x (012):X with more rectangular surface (012), where X is a dopant. By post annealing, we obtained a maximum spin Hall angle of 24 for epitaxial Bi 0.9 Sb 0.1 (012). Furthermore, we found a clear correlation between the spin Hall angle and the column height in Bi 0.9 Sb 0.1 (012) subjected to post annealing up to 215 °C and 3 h. Our findings establish a foundation for effective methodologies aimed at producing high-performance Bi 1− x Sb x in the (012) orientation on practical Si/SiO x substrates using physical vapor deposition.