N. Lazarević

Evidence for Electron-phonon Interaction in Fe1−xMxSb2 (M=Co and Cr; 0 x 0.5) Single Crystals

We have measured polarized Raman scattering spectra of the Fe{sub 1-x}Co{sub x}Sb{sub 2} and Fe{sub 1-x}Cr{sub x}Sb{sub 2} (0 {le} x {le} 0.5) single crystals in the temperature range between 15 and 300 K. The highest energy B{sub 1g} symmetry mode shows significant line asymmetry due to phonon-mode coupling-width electronic background. The coupling constant achieves the highest value at about 40 K and after that it remains temperature independent. Origin of additional mode broadening is pure anharmonic. Below 40 K the coupling is drastically reduced, in agreement with transport properties measurements. Alloying of FeSb{sub 2} with Co and Cr produces the B{sub 1g} mode narrowing, i.e., weakening of the electron-phonon interaction. In the case of A{sub g} symmetry modes we have found a significant mode mixing.

Lattice dynamics of KNi2Se2

We report the first principle calculations of the lattice dynamics of KNi

Indication of subdominant d-wave interaction in superconducting CaKFe4As4

_{2}

Sustained phase separation and spin glass in Co-doped KxFe2−ySe2 single crystals

Se

Insulating and metallic spin glass in K

_2

_{x}

together with the Raman scattering study.\ We have observed three out of four Raman active modes predicted by the factor group analysis. Calculated phonon frequencies are in good agreement with experimental findings.\ Contrary to its iron counterpart (K

Fe

_x

_{2-\delta-y}

Fe

Ni

_{2-y}

_{y}

Se