Origin of the Large Anisotropy in the \chi_3 Anomaly in URu_2Si_2

TL;DR

This paper explains the large anisotropy in the nonlinear susceptibility anomaly of URu_2Si_2 by proposing hastatic order as its microscopic origin, supported by predictions for angular anisotropy as a test.

Contribution

It introduces hastatic order as a novel explanation for the anisotropic susceptibility anomaly in URu_2Si_2, linking it to hidden order and hybridization effects.

Findings

Hastatic order naturally explains the large anisotropy.

Predictions made for angular dependence of susceptibility anomaly.

Supports hastatic order as a candidate for hidden order in URu_2Si_2.

Abstract

Motivated by recent quantum oscillations experiments on URu_2Si_2, we discuss the microscopic origin of the large anisotropy observed many years ago in the anomaly of the nonlinear susceptibility in this same material. We show that the magnitude of this anomaly emerges naturally from hastatic order, a proposal for hidden order that is a two-component spinor arising from the hybridization of a non-Kramers Gamma_5 doublet with Kramers conduction electrons. A prediction is made for the angular anisotropy of the nonlinear susceptibility anomaly as a test of this proposed order parameter for URu_2Si_2.