Increased hole mobility in anti-ThCrSi-type LaOBi co-sintered with alkaline earth metal oxides for oxygen intercalation and hole carrier doping.

Metallic anti-ThCrSi-type REOBi (RE = rare earth) with Bi square nets show superconductivity while insulating LaOBi shows high hole mobility, by expanding the c-axis length through oxygen intercalation. In this study, alkaline earth metal oxides (CaO, SrO and BaO) were co-sintered with LaOBi. CaO and BaO served as oxygen intercalants without the incorporation of Ca and Ba in LaOBi. On the other hand, SrO served not only as an oxygen intercalant but also as a hole dopant via Sr substitution for La in LaOBi. The oxygen intercalation and hole doping resulted in the expansion of the c-axis length, contributing to the improved electrical conduction. In addition, the hole mobility was enhanced up to 150 cm V s in LaOBi, which is almost double the mobility in a previous study.