Accurate and efficient simulation of photoemission spectroscopy via Kohn-Sham scattering states

Abstract

We introduce an efficient first-principles framework for simulating angle-resolved photoemission spectroscopy (ARPES) by computing photoelectron states as solutions of the Kohn-Sham equation with scattering boundary conditions. This approach is formally equivalent to the Lippmann-Schwinger formalism but offers superior computational efficiency and direct integration with plane-wave or real-space density functional theory. By enabling direct calculation of photoemission matrix elements, our method bridges the gap between intrinsic electronic properties and experimental ARPES spectra. We demonstrate its accuracy through circular dichroism ARPES simulations for monolayer graphene and bulk $2H$-WSe$_2$, achieving excellent agreement with experimental data and highlighting the critical role of pseudopotentials in describing high-energy photoelectron scattering. Our results establish a robust and accessible route for quantitative ARPES modeling, paving the way for advanced studies of orbital textures, many-body effects, and time-resolved photoemission.

Figures (4)

• Figure 1: (a) Experimental geometry used in Ref. gierz_graphene_2012. The angle of incidence is $\alpha=50^\circ$. (b) Sketch of the Brillouin zone of graphene with the region of interest highlighted in green around the $K$-point. (c) Calculated energy-integrated normalized CDAD around the $K$-point of graphene at photon energy 52 eV, and (d) at photon energy 65 eV. Results are obtained with all-electron method.
• Figure 2: (a) Comparison of the maximum intensity of the normalized CDAD at the Fermi level along $k_y = 0$ from the experiments, all-electron (AE) and pseudopotential (PP) methods. The experimental data are extracted from Ref. gierz_graphene_2012, with minus sign indicating CDAD sign reversal. (b) Angular dependence of the normalized CDAD spectra for different photon energies. The angle $\phi$ is defined in Fig. \ref{['fig:1']}(b).
• Figure 3: (a) Experimental geometry for WSe$_2$. In real space (top panel), the scattering plane is in indicated by the vertical plane while in the reciprocal space (bottom panel) it is indicated by the vertical line along the the $k_y$ direction. The angle of incidence is $\alpha = 65^{\circ}$. (b)--(e) show the TRDAD spectra of the experiment and the theory with $E - E_{\mathrm{VBM}} = -0.25$ eV in the vicinity of K-points 1 and 2, respectively.
• Figure 4: (a)--(c) CDAD texture at binding energy $E - E_{\mathrm{VBM}} = -0.25$ eV. The spectrum is antisymmetric with respect to the scattering plane and thus only half of the Brillouin zone is shown. (d) -- (f) valley-integrated CDAD as a function of binding energy for the experiment, PP with and without semicore states, respectively.