Spin Dynamics in Cuprates: Optical Conductivity of HgBa2CuO4
Abstract
The electron-boson spectral density function I2ChiOmega 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 (Omegar) proportional to the superconducting transition temperature Omegar ~= 6.3 kB.Tc. This charge channel relationship follows closely the magnetic resonance seen by polarized neutron scattering, Omegarneutron ~= 5.4 kB.Tc. The amplitudes of both peaks decrease strongly with increasing temperature. In some cases, the peak at Omegar is weak and the spectrum can have additional maxima and a background extending up to several hundred meV.