[23a-B201-1~12] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

▼ [23a-B201-11] Signatures of two-dimensional topological insulator phase in BiSb ultrathin films

〇Yuki Osada¹, Takanori Shirokura¹, Nam Hai Pham¹ (1.Tokyo Tech.)

Keywords:topological insulator

In this work, we evaluated the electrical properties of BiSb ultrathin films to explore the possibility of phase transition from 3D-TI to 2D-TI for use in topological q-bits. When BiSb thickness was reduced to below 7 nm, BiSb conductivity suddenly decreases, suggesting band gap opening in the 2D surfaces. We observed that by reducing BiSb thickness from 7 nm to 4 nm, temperature dependence of BiSb resistivity changed from metallic to nearly constant. This constant temperature dependence of resistivity is similar to those observed in the edge states of HgTe. Thus, our results suggested that BiSb ultrathin films can transform from 3D-TI to 2D-TI when thin enough, and can be a new platform for topological quantum computers.