Effects of dzyaloshinskii-moriya interactions in volborthite: Magnetic orders and thermal hall effect

Shunsuke Furukawa, Tsutomu Momoi

Research output: Contribution to journalArticlepeer-review

Abstract

Volborthite offers an interesting example of a highly frustrated quantum magnet in which ferromagnetic and antiferromagnetic interactions compete on anisotropic kagome lattices. A recent density functional theory calculation has provided a magnetic model based on coupled trimers, which is consistent with a broad 13-magnetization plateau observed experimentally. Here we study the effects of Dzyaloshinskii-Moriya (DM) interactions in volborthite. We derive an effective model in which pseudospin-12 moments emerging on trimers form a network of an anisotropic triangular lattice. Using the effective model, we show that for a magnetic field perpendicular to the kagome layer, magnon excitations from the 13-plateau feel a Berry curvature due to the DM interactions, giving rise to a thermal Hall effect. Our magnon Bose gas theory can explain qualitative features of the magnetization and the thermal Hall conductivity measured experimentally. A further quantitative comparison with experiment poses constraints on the coupling constants in the effective model, promoting a quasi-one-dimensional picture. Based on this picture, we analyze low-temperature magnetic phase diagrams using effective field theory, and point out their crucial dependence on the field direction.

Original languageEnglish
Article number034711
JournalJournal of the Physical Society of Japan
Volume89
Issue number3
DOIs
Publication statusPublished - 2020 Mar

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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