Electronic structure of new multiple band Pt-pnictide superconductors APt3P
I. A. Nekrasov+, M. V. Sadovskii+*
+Institute for Electrophysics UB RAS, 620016 Ekaterinburg, Russia
*Institute for Metal Physics UB RAS, 620990 Ekaterinburg, Russia
Abstract
We report LDA calculated band structure, densities of states and
Fermi surfaces for recently discovered Pt-pnictide superconductors
APt3P (A = Ca, Sr, La), confirming their multiple band nature.
Electronic structure is essentially three dimensional, in contrast to
Fe pnictides and chalcogenides. LDA calculated Sommerfeld coefficient
agrees rather well with experimental data, leaving little space for very strong
coupling superconductivity, suggested by experimental data on specific heat
of SrPt3P. Elementary estimates show, that the values of critical temperature
can be explained by rather weak or moderately strong coupling, while the
decrease of superconducting transition temperature Tc from Sr to La compound
can be explained by corresponding decrease of total density of states at the
Fermi level N(E F). The shape of the density of states near the Fermi level
suggests that in SrPt3P electron doping (such as replacement Sr by La)
decreases N(E F) and Tc, while hole doping (e.g. partial
replacement of Sr with K, Rb or Cs, if possible) would increase N(E F) and
possibly Tc.