I want to study the properties of NiO as a hole transporting material adapted for perovskite solar cells using Quantum ESPRESSO.
From Materials Project website, I saw that NiO can exist in different crystal structures. I intended to choose the most stable structure, but from literature I see that researchers also work with other metastable crystal structures of a material.
Knowing that any material can have more than 2 metastable structures, can someone explain to me why do I have to choose a structure and not another?