Prediction of a new phase transition in Al2O3at high pressures

摘要: [1] We use density functional theory to investigate several high-pressure polymorphs of Al 2 O 3 and predict a new stable polymorph at high pressures with post-perovskite structure. The ambient pressure R3c corundum phase transforms the Pbcn Rh (II) structure about 104 GPa. At 156 GPa, further Cmcm Pbnm perovskite is metastable all respect corundum, post-perovskite. transition takes place 120 which above same in MgSiO . Thus presence lower mantle, dissolved perovskite, will increase Our calculations also show that most likely , increasing its stability pressures.