Anti-ThCr2Si2-type RE2O2Bi (RE = rare earth) with a Bi square net is known to show an insulator-metal transition by substituting RE. In this study, La2O2Bi polycrystals with different oxygen nonstoichiometry were synthesized. As the amount of oxygen in La2O2Bi increased, the c-axis length was expanded due to the generation of an additional 4e site for excess oxygen, while the a-axis length remained almost constant, indicating the separation of Bi square nets by oxygen intercalation. Concomitantly, transformation of insulating La2O2Bi into metallic La2O2Bi occurred with the change in carrier polarity from the n- to p-type. Despite its polycrystalline form, La2O2Bi with the largest amount of oxygen showed a rather high hole mobility of 85 cm2 V-1 s-1 among other layered oxypnictides and oxychalcogenides.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)