SHIFT AND BROADENING OF OPTICAL-TRANSITIONS IN MNF2-ZN: Zn

The perburation on the optical properties of MnF2, caused by the presence of small amounts of Zn2+ ions substituted for Mn2+ ions, is studied for Zn concentrations up to 1 at.%. In nominally pure MnF2 pure electronic sharp-line and magnon sideband transitions involving the A1g6 ground state and the T1g4 excited state of Mn are observed in absorption and luminescence. These transitions shift to lower energies and broaden as the Zn concentration is increased. The broadening and shift are explained on the basis of the inhomogeneous strains introduced into the lattice by the Zn impurities and a simple strain theory of line broadening applied to MnF2 yields values for the broadening which are close to the observed values.