I’m trying to compare DFT bandgaps with experimental data. However, I’m having problems finding information on experimental bandgaps. The papers I’ve looked at just say: taken from “literature.” I know that MP provides references for some materials and has an entry for “theoretical.” Does MP have a specific entry for experimentally observed bandgap?
We do not currently list experimental references, however there are several datasets available. In particular, I would recommend this one: MPContribs (more details available at Table of Datasets — matminer 0.7.8 documentation).
However, take these experimental datasets with caution. While many experimental references are high-quality, having assembled some of these myself in the past, I’ve noticed some materials with wildly varying reported gaps (of > 1 eV in some cases!). This can be for many reasons: differing sample quality or sample preparation, different characterization methods, measurement of direct vs indirect/fundamental gap, optical vs electronic gap (e.g. there may be forbidden transitions present), mis-reporting of symmetry or polymorph or error in transcription/digitization (especially for older papers), the list goes on.
In other words, I would recommend referring to these datasets with caution and always double-checking the original reference.
Hope this helps!