The electron-boson spectral density function I^2ChiOmega responsible for carrier scattering of the high temperature superconductor HgBa2CuO4 (Tc = 90 K) is calculated from new data on the optical scattering rate. A maximum entropy technique is used. Published data on HgBa2Ca2Cu3O8 (Tc = 130 K) are also inverted and these new results are put in the context of other known cases. All spectra (with two notable exceptions) show a peak at an energy (Omega_r) proportional to the superconducting transition temperature Omega_r ~= 6.3 kB.Tc. This charge channel relationship follows closely the magnetic resonance seen by polarized neutron scattering, Omega_r^{neutron} ~= 5.4 kB.Tc. The amplitudes of both peaks decrease strongly with increasing temperature. In some cases, the peak at Omega_r is weak and the spectrum can have additional maxima and a background extending up to several hundred meV.
@article{arxiv.0901.0689,
title = {Spin Dynamics in Cuprates: Optical Conductivity of HgBa2CuO4},
author = {J. Yang and J. Hwang and E. Schachinger and J. P. Carbotte and R. P. S. M. Lobo and D. Colson and A. Forget and T. Timusk},
journal= {arXiv preprint arXiv:0901.0689},
year = {2009}
}