High-pressure modulation of altermagnetism in MnF2

We investigate the phase transition behavior and electronic band structure of MnF2 under high pressures ranging from 0 to 20 GPa based on first-principles calculations. At ambient pressure, MnF2 in the rutile structure displays antiferromagnetic properties along with significant altermagnetic characteristics. Upon increasing pressure, MnF2 undergoes sequential phase transitions from the rutile structure to the SrI2-type structure and further to the α-PbCl2-type structure. Under high pressure, all three structures of MnF2 exhibit stable altermagnetism, with the maximum spin splitting of 307.5 meV at 3 GPa for the rutile structure, 133.6 meV at 12 GPa for the SrI2-type structure, and 58.4 meV at 20 GPa for the α-PbCl2-type structure. Additionally, our findings suggest that the magnitude of spin splitting can be effectively controlled by modulating the antiferromagnetic exchange interactions and the electron hopping parameters between sublattices. This work elucidates the crystal structure, electronic structure, and altermagnetic properties of MnF2 under high pressure, providing important theoretical foundations for expanding the library of altermagnetic materials.