Title: Competing orders in pyrochlore magnets from a ${\mathbb{Z}}_2$ spin liquid perspective

Abstract

We report that the pyrochlore materials have long been predicted to harbor a quantum spin liquid, an intrinsic long-rangeentangled state supporting fractionalized excitations. Existing pyrochlore experiments, on the other hand, have discovered several weakly ordered states and a tendency of close competition amongst them. Motivated by these facts, we give a complete classification of spin-orbit-coupled ${\mathbb{Z}}_2$ spin-liquid states on the pyrochlore lattice by using the projective symmetry group (PSG) approach for bosonic spinons. For each spin liquid, we construct a mean-field Hamiltonian that can be used to describe phase transitions out of the spin liquid via spinon condensation. Studying these phase transitions, we establish phase diagrams for our mean-field Hamiltonians that link magnetic orders to specific spin liquids. In general, we find that seemingly unrelated magnetic orders are intertwined with each other and that the conventional spin orders seen in the experiments are accompanied by more exotic hidden orders. Our critical theories are categorized into z = 1 and z = 2 types, based on their spinon dispersion and Hamiltonian diagonalizability, and are shown to give distinct signatures in the heat capacity and the spin structure factor. Lastly, this study provides a clear map of pyrochlore phases for future experiments and variational Monte Carlo studies in pyrochlore materials.

Authors:

Liu, Chunxiao  ^[1];

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Halász, Gábor B. ^[2]; Balents, Leon ^[3]

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+ Show Author Affiliations

1. Univ. of California, Santa Barbara, CA (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of California, Santa Barbara, CA (United States)
3. Univ. of California, Santa Barbara, CA (United States) ; Canadian Inst.for Advanced Research, Toronto, ON (Canada)

Publication Date:

2019-08-12

Research Org.:

Univ. of California, Santa Barbara, CA (United States). Kavli Institute for Theoretical Physics

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

OSTI Identifier:

1556863

Alternate Identifier(s):

OSTI ID: 1556842

Grant/Contract Number:  

FG02-08ER46524

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 100; Journal Issue: 7; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY