Concurrent Pressure-Induced Spin-State Transitions and Jahn-Teller Distortions in MnTe

Cooperative Jahn-Teller (JT) distortion accom-panied by electromagnetic lattice coupling plays a crucial role innumerous important phenomena in materials science. The JTdistortion occurring in high-spin 3d4and 3d9configurations inoctahedral complexes is common, but similarly, large distortion dueto lifting the degeneracy of t2gorbitals has so far seldomly beenobserved. Here, we report the discovery of the pressure-inducedcooperative JT effect coupled with a large volume collapse of similar to 12.8% and a magnetic moment collapse fromS= 5/2 toS= 1/2at similar to 20.9 GPa in MnTe. Thefirst-principles calculation indicatesthat weakened p-d hybridization and enhanced d state localizationresult in lifting t2gorbital degeneracy in Mn2+(d5), which induced acooperative JT effect-triggered electromagnetic lattice coupling.Thesefindings suggest a new mechanism for the cooperative JT distortion via pressure-induced ligand distortion inantiferromagnetic materials