Nanofabrication and transport studies of Quasi-one-dimensional Topological Insulators

Quasi-one-dimensional (1D) topological insulators (TIs) promise advantages over their three-dimensional (3D) and quasi-two-dimensional (2D) counterparts, such as multiple cleavage planes, strain-induced phase transitions between weak TI, strong TI, and trivial insulator, and hosting of prototype higher-order TIs with helical hinge modes. Prototypical examples of quasi-1D TIs are Bi4I4 and Bi4Br4, which are composed of a periodic stack of atomic chains aligned to the b direction. Utilizing nanofabrication techniques, we are able to exfoliate and fabricate thin layer of field-effect transistors based on these materials and observe their transport behavior at high magnetic field and low temperature.