How to Write a Reproducible Methods Section for Computational Materials Research
“PBE functional, PAW pseudopotentials, 520 eV cutoff.” That sentence appears in thousands of computational materials papers. It is not a methods section. It is a caption. Lejaeghere et al. compared 71 elemental crystals across 15 DFT codes using 40 different potentials or basis set types (Science, 2016). Most modern codes converged, but only when parameters were carefully controlled. Hegde et al. later quantified what happens when they are not: comparing the same materials across AFLOW, Materials Project, and OQMD, formation energy variance reached 0.105 eV/atom (Phys. Rev. Materials, 2023). Up to 7% of materials disagreed on whether a compound was metallic or insulating. Fifteen percent disagreed on magnetic state. The three root causes: pseudopotential choice, DFT+U implementation, and elemental reference states. All three are routinely underreported in methods sections. ...