Quantized Anomalous Hall Effect in Magnetic Topological Insulators

• Published in: Science (American Association for the Advancement of Science) 2010-07, Vol.329 (5987), p.61-64
• Main Authors: Yu, Rui, Zhang, Wei, Zhang, Hai-Jun, Zhang, Shou-Cheng, Dai, Xi, Fang, Zhong
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Doping; Electric currents; Electrical phases; Electronic publishing; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Electrons; Exact sciences and technology; Hall effect; Insulators; Magnetic fields; Physics; Quantum hall effect (including fractional); Quantum physics; Semiconductor doping; Semiconductors; Thin films; Topology; Transition metals; Transport processes
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1187485

The anomalous Hall effect is a fundamental transport process in solids arising from the spin-orbit coupling. In a quantum anomalous Hall insulator, spontaneous magnetic moments and spin-orbit coupling combine to give rise to a topologically nontrivial electronic structure, leading to the quantized Hall effect without an external magnetic field. Based on first-principles calculations, we predict that the tetradymite semiconductors Bi₂Te₃, Bi₂Se₃, and Sb₂Te₃ form magnetically ordered insulators when doped with transition metal elements (Cr or Fe), in contrast to conventional dilute magnetic semiconductors where free carriers are necessary to mediate the magnetic coupling. In two-dimensional thin films, this magnetic order gives rise to a topological electronic structure characterized by a finite Chern number, with the Hall conductance quantized in units of e²/h (where e is the charge of an electron and h is Planck's constant).