Chapter 8 - Magnetic topological insulators: growth, structure, and properties

Abstract

Topological insulators (TIs) are an emerging group of materials with new states of quantum matter. TIs have gapless Dirac surface states protected by time-reversal symmetry (TRS), owing to a nontrivial band topology and strong spin–orbit coupling. Moreover, its surface conduction exhibits unusual spin–momentum locking features. As a result, TIs have stimulated considerable worldwide attention due to its potential applications in the fields of condensed matter physics, nanotechnology, spintronics and materials science, and so on. Highlighting TIs’ compelling physical, electronic, and magnetic properties, in this chapter, we review the methods for implementing magnetic TIs and its potential spintronics applications. First, we introduce the unique surface states of TIs, followed by the description of its composition and crystal structures. Then, we summarize the various synthetic methods, clarify the advantages and disadvantages of these methods, and propose that the molecular-beam epitaxy is the most suitable preparation method. Finally, we introduce two ways to break the TRS, and then discuss in detail the various properties of the TIs with the emphases on the magnetic TIs, magnetic proximity effect, spin-transfer torque effects and its potential applications in magnetic random access memory.