Optical spectrum of Cu₂MnAl

The optical absorption spectrum of Cu₂MnAl is calculated within the RPA using energy values and wavefunctions determined by the tight-binding orthogonalised plane wave (TB OPW) method and is compared with experiment. It is found that the transitions between OPW in the hybridised states dominantly contribute to the main structure of the spectrum. The correlation effect due to the electron-hole interaction is evaluated taking into account the G(q, omega ) function which describes correlation and exchange effects. The result suggests that the correlated electron-hole pair has a broadening effect on the optical spectrum, particularly on the prominent peak.