Photoinduced transition between conventional and topological insulators in two-dimensional electronic systems.
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.
Inoue
Jun-Ichi
J
National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan. INOUE.Junichi@nims.go.jp
Tanaka
Akihiro
A