Tunneling into Bilayer Iridate Sr₃Ir₂O₇

Spin-orbit coupling in the iridates links magnetism to the flow of electric charge. We adapt the Eliashberg procedure and calculate the electron tunneling density of states in the bilayer iridate Sr₃Ir₂O₇. Fits to measured tunneling conductance allow us to estimate the product of the electron-magnon coupling strength with the magnon density of states. We compare the results to expectations based on recent neutron and x-ray scattering from magnons in this material and find good agreement for the location of van Hove singularities in the magnon density of states.