CoAs: The line of 3d demarcation

TL;DR

This paper investigates the electronic and magnetic properties of CoAs, revealing its proximity to ferromagnetic instability through experimental measurements and theoretical calculations, and providing detailed insights into its Fermi surface.

Contribution

It presents the growth, experimental characterization, and density functional theory analysis of CoAs single crystals, highlighting its paramagnetic nature and proximity to ferromagnetism.

Findings

CoAs is primarily paramagnetic.

Quantum oscillations support the Fermi surface calculations.

Evidence suggests CoAs is near a ferromagnetic instability.

Abstract

Transition metal-pnictide compounds have received attention for their tendency to combine magnetism and unconventional superconductivity. Binary CoAs lies on the border of paramagnetism and the more complex behavior seen in isostructural CrAs, MnP, FeAs, and FeP. Here we report the properties of CoAs single crystals grown with two distinct techniques along with density functional theory calculations of its electronic structure and magnetic ground state. While all indications are that CoAs is paramagnetic, both experiment and theory suggest proximity to a ferromagnetic instability. Quantum oscillations are seen in torque measurements up to 31.5~T, and support the calculated paramagnetic Fermiology.