Impact of work function induced electric fields on laser-based angle-resolved photoemission spectroscopy

We examine the effects of the electric fields caused by the difference in work function between a sample and its surroundings in laser-based angle-resolved photoemission spectroscopy (laser ARPES) experiments. To simulate these effects we created several samples and surrounding puck geometries using SimIon 8.0 modeling software, and found that in most cases the system can be approximated by a circular sample mounted on an infinite conducting plane. Experimental measurements of the cuprate superconductor Bi2Sr2CaCu2O8+δ mounted on copper, aluminum, and graphite pucks confirmed the model's accuracy. Both the model and experimental data showed that work-function-induced fields have a significant effect on the outgoing trajectories of electrons for kinetic energies up to six times the work function difference between the sample and the puck. However, with the exception of effects very close to the sample edge, all electric field effects can be taken into account using linear corrections.