Spin nematic state as a candidate of the hidden order phase of URu$_2$Si$_2$

TL;DR

This paper proposes that a spin nematic state could explain the hidden order phase in URu$_2$Si$_2$, aligning well with experimental observations and temperature-dependent spin anisotropy data.

Contribution

It introduces the spin nematic state as a novel candidate for the hidden order phase, successfully explaining experimental features and temperature dependence.

Findings

Explains broken four-fold symmetry in URu$_2$Si$_2$

Reproduces temperature dependence of spin anisotropy

Provides strong evidence for spin nematic order

Abstract

Motivated by the recent discovery of broken four-fold symmetry in the hidden order phase of URu$_2$Si$_2$[R. Okazaki et al., Science {\bf 331}, 439 (2011)], we examine a scenario of a spin nematic state as a possible candidate of the hidden order phase. We demonstrate that the scenario naturally explains most of experimental observations, and furthermore, reproduces successfully the temperature dependence of the spin anisotropy detected by the above-mentioned experiment in a semi-quantitative way. This result provides strong evidence for the realization of the spin nematic order.