A pseudofermion functional renormalization group study of dipolar-octupolar pyrochlore magnets

TL;DR

This study uses pseudofermion functional renormalization group methods to analyze dipolar-octupolar pyrochlore magnets, revealing a phase diagram with quantum spin liquids and magnetic orders, and matching experimental neutron scattering data.

Contribution

It applies PFFRG to the XYZ Hamiltonian of dipolar-octupolar pyrochlores, identifying four phases and supporting a quantum spin liquid ground state in Ce$_2$Zr$_2$O$_7$.

Findings

Identified four distinct magnetic phases including quantum spin ices.

Mapped out the phase diagram with quantum disordered and ordered states.

Reproduced experimental neutron scattering features qualitatively.

Abstract

Motivated by recent experiments on Ce$_2$Zr$_2$O$_7$ that reveal a dynamic, liquid-like ground state, we study the nearest neighbor XYZ Hamiltonian of dipolar-octupolar pyrochlore magnets with the pseudofermion functional renormalization group (PFFRG), which is numerically implemented by the SpinParser software. Taking the interaction between the octupolar components to be dominant and antiferromagnetic, we map out the phase diagram demarcating the quantum disordered and magnetically ordered states. We identify four distinct phases, namely the $0$-flux and $\pi$-flux quantum spin ices, and the all-in-all-out magnetic orders along the local $z$ and $x$ axes. We further use the static two-spin correlations output by the PFFRG algorithm to compute the polarized neutron scattering cross-sections, which are able to capture several qualitative features observed experimentally, in the materially relevant parameter regime that stabilizes the $\pi$-flux quantum spin ice. Our results provide support for a quantum spin liquid ground state in Ce$_2$Zr$_2$O$_7$.