Dynamical axion field in topological magnetic insulators

作者:Li Rundong*; Wang Jing; Qi Xiao Liang; Zhang Shou Cheng
来源:Nature Physics, 2010, 6(4): 284-288.
DOI:10.1038/NPHYS1534

摘要

Axions are weakly interacting particles of low mass, and were postulated more than 30 years ago in the framework of the Standard Model of particle physics. Their existence could explain the missing dark matter of the Universe. However, despite intensive searches, axions have yet to be observed. Here we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In particular, we show that the axion coupling enables a nonlinear modulation of the electromagnetic field, leading to attenuated total reflection. We propose a new optical-modulator device based on this principle.