Density-functional theory study on the electronic properties of laves phase superconductor CaIr2

In this work we have used density-functional theory methods such as full-potential local orbital minimum basis (FPLO) and ELK-flapw to study the electronic structure of newly discovered Laves phase superconductor CaIr2. The calculation of density of states (DOS) indicates that the bands near Fermi level are mostly occupied by the d-electrons of iridium. The simulation of de Haas-van Alphen (dHvA) effect has been performed by using Elk code to check the Fermi surface topology. The results show that there exist four Fermi surfaces in CaIr2, including two electron-type and two hole-type surfaces. The optical response properties of CaIr2 have been calculated in the dipole-transition approximations combined with including intra-band Drude-like terms. In the optical spectrum sigma(omega) shows that the crossover from intra-band to inter-band absorption occur near 1.45 eV. Further analysis on the electron energy loss spectra (EELS) matches the conclusion from that of optical conductivity sigma(omega)