Spin-phonon interaction and short-range order in Mn3Si2Te6

The vibrational properties of ferrimagnetic Mn3Si2Te6 single crystals are investigated using Raman spec-troscopy and density functional theory calculations. Eighteen Raman-active modes are identified, 14 of which are assigned according to the trigonal symmetry. Four additional peaks, obeying the A1g selection rules, are attributed to the overtones. The unconventional temperature evolution of the A51g mode self-energy suggests a competition between different short-range magnetic correlations that significantly impact the spin-phonon interaction in Mn3Si2Te6. The research provides comprehensive insight into the lattice properties, studies their temperature dependence, and shows arguments for the existence of competing short-range magnetic phases in Mn3Si2Te6.