You are currently viewing the editor's summary.View Full Text
Shining light on a peculiar coupling
One of the long-standing predictions regarding topological insulators is the magnetoelectric effect, a coupling between a material's magnetic and electric properties. Thanks to this coupling, Maxwell's equations inside topological insulators are modified, resulting in so-called axion electrodynamics. Wu et al. used time-domain terahertz (THz) spectroscopy to observe signatures of these unusual electrodynamics in a thin film of Be2Se3. They detected tiny changes to the polarization of THz light after it passed through the thin film, confirming the expected quantization of the magnetoelectric coupling.
Science, this issue p. 1124