Subsystem symmetries, critical Bose surface, and immobile excitations in an extended compass model

TL;DR

This paper introduces an extended compass model with subsystem symmetries that constrains spin excitation mobility, revealing a critical Bose surface, a nodal-line spin liquid, and immobile excitations akin to fractons, with potential experimental relevance.

Contribution

The study proposes a new extended compass model exhibiting subsystem symmetries, critical Bose surface, and immobile excitations, advancing understanding of quantum criticality and spin liquids.

Findings

Presence of a critical Bose surface along entire $k_x$ and $k_y$ axes.

Identification of a nodal-line spin liquid with nematic instability.

Discovery of immobile excitations analogous to fractons in the ferro-quadrupole phase.

Abstract

We propose an extended compass model that hosts subsystem symmetries and has potential experimental relevance with 3d transition metal compounds. The subsystem symmetries strongly constrain the mobility of spin excitations and lead to profound consequences. At the quantum critical point we find the presence of "critical Bose surface" along the entire $k_x$ and $k_y$ axis. Across which we find a nodal-line spin liquid that undergoes nematic instability at low temperatures. In the ferro-quadrupole phase, we find that one excitation is immobile individually analogous to "fractons".