Topological Insulator Materials

TLDR

Topological insulators are a new quantum state of matter characterized by edge or surface states arising from the topological nature of bulk wave functions, and they hold promise for revealing novel quantum phenomena. This review aims to provide a pedagogical overview of topological insulator materials, focusing on basic theory and material properties. The review surveys the historical development and fundamental theories of topological insulators, catalogs known materials up to May 2013, discusses experimental confirmation methods, synthesis techniques, defect chemistry for bulk insulation, and examines transport properties, Dirac fermion physics, and quantum oscillation signatures. The authors emphasize that careful analysis of quantum oscillations enables unambiguous identification of surface Dirac fermions via transport measurements.

Abstract

Topological insulators represent a new quantum state of matter which is characterized by peculiar edge or surface states that show up due to a topological character of the bulk wave functions. This review presents a pedagogical account on topological insulator materials with an emphasis on basic theory and materials properties. After presenting a historical perspective and basic theories of topological insulators, it discusses all the topological insulator materials discovered as of May 2013, with some illustrative descriptions of the developments in materials discoveries in which the author was involved. A summary is given for possible ways to confirm the topological nature in a candidate material. Various synthesis techniques as well as the defect chemistry that are important for realizing bulk-insulating samples are discussed. Characteristic properties of topological insulators are discussed with an emphasis on transport properties. In particular, the Dirac fermion physics and the resulting peculiar quantum oscillation patterns are discussed in detail. It is emphasized that proper analyses of quantum oscillations make it possible to unambiguously identify surface Dirac fermions through transport measurements. The prospects of topological insulator materials for elucidating novel quantum phenomena that await discovery conclude the review.