Direct extraction of the eliashberg function for electron-phonon coupling: A case study of be(1010̄)

A systematic procedure to directly extract the Eliashberg function for electron-phonon coupling was discussed using the high resolution angle-resolved photoemission spectroscopy (ARPES) data. Systematic tests were carried out to assess the effects of various parameters involved in the fitting and the robustness of the procedure against data imperfections. It was shown that the maximum entropy method (MEM) was used to overcome the data imperfections and numerical instability. It was found that ARPES allowed wider applicability and measurements along different directions compared to other traditional tunneling methods