AZrO ₃ (A = Ca, Pb) (110) And (001) Surface Structure And Stabilization Mechanism

The cubic AZrO3(A=Pb, Ca)(001) and (110) surfaces were investigated by densityfunctional theory method in this study, involving surface atomic and electronic structuresof (110) polar surfaces and the influence of (001) surface on the stability phase diagramof (110) polar terminations. The computational results indicated that a somewhatconsiderable change in geometric structure appears for the (110) polar terminations ofAZrO3(A=Pb, Ca). Also, an oxygen octahedral rotation can be observed for mostterminations. Furthermore, significant electronic structure changes can also be found for(110) polar terminations of AZrO3(A=Pb, Ca), involving a filling of conduction bandleading to metallic characteristics for the AZrO (A=Pb, Ca) termination and theformation of peroxo bond resulting in electron redistribution from two oxygen atom onthe first layer of O2termination. However, there is a less change in electronic structurefor the nonstoichiometric (110) polar terminations of AZrO3(A=Pb, Ca) relative torespective bulk. Furthermore, the calculated results show that the polarity compensationcan be completed well either via electronic structure change for stoichiometricterminations or via surface stoichiometric change for nonstoichiometric surfaces. In thisinvestigation, the surface grand potential technology was employed to evaluate the effectof chemical potential on terminations. Also, a thermodynamic stability phase diagramwas constructed, from which one can reasonably draw a conclusion that all investigatedterminations can be stabilized in some distinct areas.