Itinerant Ferromagnetism and Quantum Criticality in Sc$_3$In

TL;DR

This study uses density functional theory to explore itinerant ferromagnetism and quantum criticality in hexagonal Sc$_3$In, revealing potential for tuning magnetic properties via uniaxial strain.

Contribution

It demonstrates the sensitivity of magnetic properties to structural parameters and suggests uniaxial strain as a means to reach quantum criticality in Sc$_3$In.

Findings

Fermi energy lies in flat Sc d bands causing a density of states peak.

Magnetizations are enhanced beyond experimental values, indicating quantum critical fluctuations.

Quantum critical point may be achieved through uniaxial strain, not pressure.

Abstract

The electronic structure and magnetic properties of hexagonal Sc$_3$In are calculated within density functional theory. We find that the Fermi energy lies in a region of flat Sc $d$ derived bands leading to a peak in the density of states and Stoner ferromagnetism. The calculated local spin density and generalized gradient approximation spin magnetizations are both enhanced with respect to experiment, which is an indication of significant quantum critical fluctuations, neglected in these approximations. We find, as expected, that the ferromagnetism is initially enhanced under pressure, meaning that the critical point cannot be reached with modest pressure. However, we find that the density of states peak around the Fermi energy and the calculated density functional magnetic properties are sensitive to the $c/a$ ratio, so that the quantum critical point may be reached under uniaxial strain.