Title: Quantum liquid from strange frustration in the trimer magnet Ba4Ir3O10

Abstract

Abstract Quantum spin systems such as magnetic insulators usually show magnetic order, but such classical states can give way to quantum liquids with exotic entanglement through two known mechanisms of frustration: geometric frustration in lattices with triangle motifs, and spin-orbit-coupling frustration in the exactly solvable quantum liquid of Kitaev’s honeycomb lattice. Here we present the experimental observation of a new kind of frustrated quantum liquid arising in an unlikely place: the magnetic insulator Ba ₄ Ir ₃ O ₁₀ where Ir ₃ O ₁₂ trimers form an unfrustrated square lattice. The crystal structure shows no apparent spin chains. Experimentally we find a quantum liquid state persisting down to 0.2 K that is stabilized by strong antiferromagnetic interaction with Curie–Weiss temperature ranging from −766 to −169 K due to magnetic anisotropy. The anisotropy-averaged frustration parameter is 2000, seldom seen in iridates. Heat capacity and thermal conductivity are both linear at low temperatures, a familiar feature in metals but here in an insulator pointing to an exotic quantum liquid state; a mere 2% Sr substitution for Ba produces long-range order at 130 K and destroys the linear-T features. Although the Ir ⁴⁺ (5d ⁵ ) ions in Ba ₄ Ir ₃ O ₁₀ appear tomore » form Ir ₃ O ₁₂ trimers of face-sharing IrO ₆ octahedra, we propose that intra-trimer exchange is reduced and the lattice recombines into an array of coupled 1D chains with additional spins. An extreme limit of decoupled 1D chains can explain most but not all of the striking experimental observations, indicating that the inter-chain coupling plays an important role in the frustration mechanism leading to this quantum liquid.« less

Authors:

Cao, Gang ;

• Search DOE PAGES for author "Cao, Gang"
• Search DOE PAGES for ORCID "0000-0001-9779-430X"

Zheng, Hao; Zhao, Hengdi; Ni, Yifei; Pocs, Christopher A.; Zhang, Yu; Ye, Feng; Hoffmann, Christina; Wang, Xiaoping ;

• Search DOE PAGES for author "Wang, Xiaoping"
• Search DOE PAGES for ORCID "0000-0001-7143-8112"

Lee, Minhyea; Hermele, Michael; Kimchi, Itamar

• Search DOE PAGES for author "Kimchi, Itamar"
• Search DOE PAGES for ORCID "0000-0002-5152-2605"

Publication Date:

Wed May 06 00:00:00 EDT 2020

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); US Army Research Office (ARO)

OSTI Identifier:

1765426

Alternate Identifier(s):

OSTI ID: 1897821

Grant/Contract Number:  

AC05-00OR22725; SC0014415; DMR-1712101; 1903888; DMR-1157490; W911NF-17-1-0482

Resource Type:

Published Article

Journal Name:

npj Quantum Materials

Additional Journal Information:

Journal Name: npj Quantum Materials Journal Volume: 5 Journal Issue: 1; Journal ID: ISSN 2397-4648

Publisher:

Nature Publishing Group

Country of Publication:

United Kingdom

Language:

English

Subject:

36 MATERIALS SCIENCE; magnetic properties and materials; phase transitions and critical phenomena