I'm working on a data-driven project involving material properties and I'm wondering about the following:
I know that the notion of band gap and electrical conductivity are inversely related, and the former can help in classifying materials in metals, semiconductors and insulators. Nevertheless, I would like to know if there are cases where materials can exhibit a very low band gap yet not be conducting. I guess there are, as I expect conductivity depends on a variety of factors that won't include the band gap alone.
