Photoinduced Transition between Conventional and Topological Insulators in Two-Dimensional Electronic Systems

Abstract

Manipulating the topological properties of insulators, encoded in invariants such as the Chern number and its generalizations, is now a major issue for realizing novel charge or spin responses in electron systems. We propose that a simple optical means, subjecting to a driving laser field with circular polarization, can be fruitfully incorporated to this end. Taking as a prototypical example the two-band insulator first considered by Haldane, we show how the electron system can be tuned through phases associated with different Chern numbers as the laser intensity is adiabatically swept, i.e., a photoinduced analog of the quantum Hall plateau transition. The implications of our findings include the possibility of laser tuning a conventional insulator into a quantum spin Hall system. DOI: http://dx.doi.org/10.1103/PhysRevLett.105.017401 Received 1 October 2009Revised 10 May 2010Published 28 June 2010© 2010 The American Physical Society