Terahertz conductivity of a metal-organic hybrid Kagom\'e lattice: A candidate spin liquid

Recent theoretical studies predict that the optical conductivity of a spin liquid should exhibit power law behavior in frequency at low temperatures. Materials with the Kagom\'e structure are the most promising candidates for observing spin liquid behavior due to their high degree of magnetic frustration. We have measured the optical conductivity of Cu(1, 3-bdc), a spin-1/2 Kagom\'e lattice material, in the range 0.5 - 2 THz. We compare these results to the theoretical predictions and comment on the implications for the existence of a spin liquid state in this material.