Magnetotransport measurements as a tool for searching 3D topological insulators

Abstract

The paper covers some measurement aspects of transport of electrons through metals and semiconductors in magnetic field – magnetotransport – allowing for the determination of electrical parameters characteristic of three-dimensional (3D) topological insulators (TI) (i.e. those that behave like an insulator inside their volume and have a conductive layer on their surface). A characteristic feature of the 3D TI is also a lack of differences between the chemical composition of the conductive surface and the interior of the material tested and the fact that the electron states for its surface conductivity are topologically protected. In particular, the methods of generating strong magnetic fields, obtaining low temperatures, creating electrical contacts with appropriate geometry were presented, and the measurement methods were reviewed. In addition, the results of magnetotransport measurements obtained for two volumetric samples based on the HgCdTe compound grown with the molecular beam epitaxy method are presented.