Pressure-Tuned Spin and Charge Ordering in an Itinerant Antiferromagnet

TL;DR

This study investigates how applying high pressure suppresses spin and charge order in elemental chromium, revealing exponential decay and a harmonic scaling relationship, and links this suppression to increased electron kinetic energy.

Contribution

It provides direct measurements of pressure-induced suppression of spin and charge order in chromium near its quantum critical point using advanced x-ray techniques.

Findings

Spin and charge order decrease exponentially with pressure.

Order maintains harmonic scaling over decades of intensity.

Destruction of antiferromagnetism linked to increased electron kinetic energy.

Abstract

Elemental chromium orders antiferromagnetically near room temperature, but the ordering temperature can be driven to zero by applying large pressures. We combine diamond anvil cell and synchrotron x-ray diffraction techniques to measure directly the spin and charge order in the pure metal at the approach to its quantum critical point. Both spin and charge order are suppressed exponentially with pressure, well beyond the region where disorder cuts off such a simple evolution, and they maintain a harmonic scaling relationship over decades in scattering intensity. By comparing the development of the order parameter with that of the magnetic wavevector, it is possible to ascribe the destruction of antiferromagnetism to the growth in electron kinetic energy relative to the underlying magnetic exchange interaction.