  A finite electronic band gap is a standard filter in high-throughput
screening of materials using density functional theory (DFT). However, because
of the systematic underestimation of band gaps in standard DFT approximations,
a number of compounds may incorrectly be predicted metallic. In a more accurate
treatment, such materials may instead appear as low band gap materials and
could e.g. have good thermoelectric properties if suitable doping is feasible.
To explore this possibility, we performed hybrid functional calculations on
1093 cubic materials listed in the MaterialsProjects database with four atoms
in the primitive unit cell, spin-neutral ground state, and a formation energy
within 0.3 eV of the convex hull. Out of these materials, we identified eight
compounds for which a finite band gap emerges. Evaluating electronic and
thermal transport properties of these compounds, we found the compositions
MgSc2 Hg and Li2 CaSi to exhibit promising thermoelectric properties. These
findings underline the potential of reassessing band gaps and band structures
of compounds to indentify additional potential thermoelectric materials.
