katch wreck"Polarization-dependent #terahertz #magnetospectroscopy measurements revealed Zeeman splittings & #diamagnetic shifts, demonstrating a large #phonon #magnetic moment. Films in the topological phase exhibited phonon magnetic moment values that were larger than those in the topologically trivial samples by 2 orders of magnitude..the sign of the effective phonon g-factor was opposite in the two phases, a signature of the #topological transition according to our model"