Abstract
We present a Wannier-based method to calculate the Chern-Simons orbital magnetoelectric coupling in the framework of first-principles density-functional theory. In view of recent developments in connection with strong topological insulators, we anticipate that the Chern-Simons contribution to the magnetoelectric coupling could, in special cases, be as large or larger than the total magnetoelectric coupling in known magnetoelectrics, such as CrO. The results of our calculations for the ordinary magnetoelectrics CrO, BiFeO, and GdAlO confirm that the Chern-Simons contribution is quite small in these cases. On the other hand, we show that, if the spatial-inversion and time-reversal symmetries of the topological insulator BiSe are broken by hand, large induced changes appear in the Chern-Simons magnetoelectric coupling.
1 More- Received 28 October 2010
DOI:https://doi.org/10.1103/PhysRevB.83.085108
©2011 American Physical Society