Field-induced spin-density wave beyond hidden order in URu2Si2

TL;DR

This study uses advanced high-field neutron scattering to identify a field-induced spin-density wave in URu2Si2, providing new insights into its mysterious hidden-order phase and its relationship with magnetic fluctuations and Fermi surface topology.

Contribution

The paper reports the first direct identification of a spin-density wave in URu2Si2 under high magnetic fields, advancing understanding of its hidden-order phase.

Findings

Identification of a spin-density wave with wavevector (0.6 0 0)

Link between magnetic structure and Fermi surface topology

Insight into the transition from hidden order to magnetic order

Abstract

URu2Si2 is one of the most enigmatic strongly-correlated-electron systems and offers a fertile testing ground for new concepts in condensed matter science. In spite of >30 years of intense research, no consensus on the order parameter of its low-temperature hidden-order phase exists. A strong magnetic field transforms the hidden order into magnetically-ordered phases, whose order parameter has also been defying experimental observation. Here, thanks to an instrumentation breakthrough in high-field neutron scattering, we identify the field-induced phases of URu2Si2 as a spin-density-wave state with wavevector k1 = (0.6 0 0). The transition to the spin-density wave represents a unique touchstone for understanding the hidden-order phase. An intimate relationship between this magnetic structure, the magnetic fluctuations, and the Fermi surface is emphasized, calling for dedicated band structure calculations.