Pressure-induced s-band ferromagnetism in alkali metals

TL;DR

This study uses first-principles calculations to show that applying pressure to alkali metals can induce s-band ferromagnetism by stabilizing open structures with localized electrons, predicting ferromagnetic phases in potassium.

Contribution

It reveals pressure-induced ferromagnetism in alkali metals through first-principles density functional theory, identifying specific structures and conditions for ferromagnetic phases.

Findings

Ferromagnetic phases found in lithium-IV-type, simple cubic, and hexagonal structures.

Potassium is predicted to become ferromagnetic around 20 GPa.

Pressure stabilizes open structures with localized interstitial electrons.

Abstract

First-principles density-functional-theory calculations show that compression of alkali metals stabilizes open structures with localized interstitial electrons which may exhibit a Stoner-type instability towards ferromagnetism. We find ferromagnetic phases of the lithium-IV-type, simple cubic, and simple hexagonal structures in the heavier alkali metals, which may be described as s-band ferromagnets. We predict that the most stable phases of potassium at low temperatures and pressures around 20 GPa are ferromagnets.