Narrow-gap semiconducting properties of KMgBi with multiband feature

KMgBi single crystals have been grown successfully by using the Bi flux method. KMgBi shows a semiconducting behavior with a metal-semiconductor transition in high temperature regions. Moreover, both electron- and hole-type carriers exist in KMgBi with a strong temperature dependence of carrier concentrations and mobilities. These results suggest that KMgBi is a narrow-band semiconductor with multiband features in the bulk rather than a semimetal as predicted theoretically. On the other hand, KMgBi exhibits a resistivity plateau in low temperature regions, similar to other topological insulators. It implies that there might be a nontrivial topological surface state in KMgBi.