Fig. 5

(Top half) Structures of clean surface of K2CsSb (111) and the surfaces with different terminations used for DFT calculations. Each surface is labeled surface 1–4. (Bottom half) The clean surfaces after O2 adsorption. There are side view images (top) and top view images. Purple circles indicate potassium, brown circles indicate antimony, green circles indicate cesium, and red circles indicate oxygen.