Single-crystal Structure Of Hobaco_4o_7 At Ambient Conditions, At Low Temperature,and At High Pressure

摘要

We show that the correct space group of HoBaCo_4O_7 at ambient conditions is P6_3 mc and that no temperature-induced or pressure-induced structural phase transition occurs down to 100 K or up to 9 GPa. The compressibility of HoBaCo_4O_7 is mainly determined by a combination of bond compression and changes in the three-membered and six-membered rings of the kagome layers. HoBaCo_4O_7 is more compressible than structurally related compounds due to the comparatively compressible Co-O bonds. The structural analysis allows us to propose an atomistic model for the extremely high oxygen incorporation capability of HoBaCo_4O_7.