Influence of antiferromagnetic spin ordering on the far-infrared active optical phonon modes of $\alpha$-MnSe
D. M. Djoki\'{c}, Z. V. Popovi\'{c}, and F. R. Vukajlovi\'{c}

The effects of spin-phonon interaction and magnetic anisotropy on the temperature dependence of the infrared optical phonon modes in the antiferromagnetic $\alpha $-MnSe are investigated by use of Green's function formalism within $1/z$\ perturbation framework. The renormalization effects\ are calculated explicitly as a function of temperature, phonon-phonon and spin-phonon interaction constants. Temperature dependence of the renormalized LO phonon frequencies of the $F_{1u}$ infrared active and combinational phonon modes are calculated and compared with experimental data. We have shown that the inclusion of anisotropy is necessary in order to get a good quantitative agreement with the experiment.

© 2008 The American Physical Society.