Open AccessTopological and magnetic phase transitions in Bi2 3
Author(s) -
Hosub Jin,
Jino Im,
Arthur J Freeman
Publication year - 2011
Publication title -
physical review. b, condensed matter and materials physics
Language(s) - English
Resource type - Journals
eISSN - 1538-4489
pISSN - 1098-0121
DOI - 10.1103/physrevb.84.134408
Subject(s) - topological order , topological insulator , topology (electrical circuits) , physics , condensed matter physics , coupling (piping) , quantum phase transition , symmetry protected topological order , phase transition , t symmetry , quantum , quantum mechanics , materials science , mathematics , combinatorics , metallurgy , superconductivity
When topological insulators meet broken time-reversal symmetry, they bring forth many novel phenomena, such as topological magnetoelectric, half-quantum Hall, and quantum anomalous Hall effects. From the well-known quantum spin Hall state in Bi2Se3 thin films, we predict various topological and magnetic phases when the time-reversal symmetry is broken by magnetic ion doping. As the magnetic ion density increases, the system undergoes successive topological or magnetic phase transitions due to variation of the exchange field and the spin-orbit coupling. In order to identify the topological phases, we vary the spin-orbit coupling strength from zero to the original value of the system and count the number of band crossings between the conduction and valence bands, which directly indicates the change of the topological phase. This method provides a physically intuitive and abstract view to figure out the topological character of each phase and the phase transitions between them.open121