Electronic structure and electron–phonon interaction in YAl2Si2

We calculate the electronic structure, phonon spectrum and electron–phonon (EP) interaction for YAl2Si2 using the full-potential, density-functional-based method. The Y 4d-like band crosses the Fermi level. The main contribution to the density of states (DOS) at the Fermi level comes from Y 4d-states. Our results for the phonon DOS and the Eliashberg spectral function show that in-plane bond-stretching modes have high frequency and couple more strongly to the electrons. Both the calculated EP coupling constant λλ (0.31) and the estimated superconducting transition temperature TCTC (0.15 K with μ*∼0.15μ*∼0.15) are very low in YAl2Si2. The differences of electronic structure, phonon structure and transport behavior between YAl2Si2 and CaAl2Si2 are discussed.