Sr$_2$VO$_3$FeAs: A Nanolayered Bimetallic Iron Pnictide Superconductor

TL;DR

This paper investigates Sr$_2$VO$_3$FeAs, a novel nanolayered iron pnictide superconductor with a unique Fermi surface geometry, differing from previous compounds, and explores its electronic structure using density functional theory.

Contribution

It reveals the distinct Fermi surface features of Sr$_2$VO$_3$FeAs caused by the V bilayer, providing new insights into iron pnictide superconductors.

Findings

Sr$_2$VO$_3$FeAs has a different Fermi surface geometry than previous iron pnictides.

The V bilayer introduces bands crossing the Fermi level, affecting electronic properties.

Coupling between layers is weak, but impacts Fermi surface nesting.

Abstract

One of the unifying concepts in the iron-pnictide superconductors, both for the mechanism of magnetic ordering and of unconventional order parameter character, has been the electron and hole Fermi surfaces that are approximately nested. Using the density functional methods that have predicted Fermi surfaces correctly in SrFe$_2$P$_2$, we find that the recently reported superconducting Sr$_2$VO$_3$FeAs, with $T_c$=37 K and no apparent competition between magnetism and superconductivity, possesses different Fermi surface geometry and character than previous classes of iron pnictides. The intervening layer (a V bilayer) gives rise to bands that cross the Fermi level. Coupling to the FeAs layer is small except for interaction along the zone boundary, however that coupling degrades the Fermi surface nesting. Sr$_2$VO$_3$FeAs, with its alternating layers of open shell atoms, deserves further close study that should help to understand the origin of the properties of iron pnictide compounds.