Enhanced spin density wave in LaOFeSb

TL;DR

This paper predicts that LaOFeSb exhibits a stronger spin density wave and potentially higher superconducting transition temperature than related compounds, based on first-principles calculations of its atomic, electronic, and magnetic structures.

Contribution

It introduces the hypothetical compound LaOFeSb and analyzes its properties, revealing enhanced SDW characteristics and potential for higher superconductivity.

Findings

LaOFeSb prefers a stripe-type antiferromagnetic phase with larger Fe moments.

The SDW phase favors an orthorhombic structure, unlike the NM phase.

Electronic structure shows increased Fermi surface nesting, indicating potential for higher Tc.

Abstract

We predict atomic, electronic, and magnetic structures of a hypothetical compound LaOFeSb by first-principles density-functional calculations. It is shown that LaOFeSb prefers a stripe-type antiferromagnetic phase (i.e., spin density wave (SDW) phase) to the non-magnetic (NM) phase, with a larger Fe spin moment and greater SDW-NM energy difference than those of LaOFeAs. The SDW phase is found to favor the orthorhombic structure while the tetragonal structure is more stable in the NM phase. In the NM-phase LaOFeSb, the electronic bandwidth near the Fermi energy is reduced compared with LaOFeAs, indicating smaller orbital overlap between Fe $d$ states and subsequently enhanced intra-atomic exchange coupling. The calculated Fermi surface in the NM phase consists of three hole and two electron sheets, and shows increased nesting between two hole and two electron sheets compared with LaOFeAs. Monotonous changes found in our calculated material properties of LaOFePn (Pn=P, As, and Sb), along with reported superconducting properties of doped LaOFeP and LaOFeAs, suggest that doped LaOFeSb may have a higher superconducting transition temperature.