Low-Energy Excitations in the Quantum Spin-Liquid $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$

A. Pustogow, E. Zhukova, B. Gorshunov +4

The electrodynamic response of the organic spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$ has been measured in an extremely wide energy range ($10^{-13}$ to 2 eV) as a func…