I'm trying to calculate the band structures of some small-gap materials like InSb, GaSb using Quantum Espresso. However, using the conventional pseudopotentials gives a zero gap with an inverted band order. To solve this problem, some references suggest to use the MBJLDA (Modified Becke-Johnson exchange + local density approximation) pseudopotential. But I could not find either where to download this potential or how to implement it in Quantum Espresso. If anyone could suggest me a way, it would be highly appreciated. Thank you very much.