Calendar of Events

Speaker: Diyar Talbayev (Tulane University)

Spatial symmetries determine how natural and artificial materials interact with light. For example, chiral molecules can cause the rotation of the polarization plane of linearly polarized light, an effect known as optical activity. Magnetic materials feature broken time-reversal symmetry, which can also lead to polarization rotation via the Faraday effect. Magneto-chiral materials combine chirality with broken time-reversal symmetry. A new effect known as nonreciprocal directional anisotropy arises under such symmetry conditions, which results in the difference of transmitted light intensity in the forward and backward directions as measured with unpolarized light. The nonreciprocal directional anisotropy can also be found more generally in noncentrosymmetric systems in magnetic field. We will consider several cases of natural and artificial materials that lack inversion symmetry as well as time reversal symmetry and their interaction with polarized terahertz-frequency light. We will observe how light can inform us of the presence or absence of certain symmetries while also providing insight in the fundamental properties of matter through the spectroscopy of low-energy spin and lattice dynamics.

Host:  Sang-Wook Cheong