Thermodynamic Evidence of Proximity to a Kitaev Spin Liquid in Ag3LiIr2O6

• Published in: Physical review letters 2019-12, Vol.123 (23)
• Main Authors: Bahrami, Faranak, Lafargue-Dit-Hauret, William, Lebedev, Oleg I, Movshovich, Roman, Yang, Hung-Yu, Broido, David, Rocquefelte, Xavier, Tafti, Fazel
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Interlayers; Ising model; Long range order; Magnetic permeability; Magnets; Material Science; MATERIALS SCIENCE; Signatures; Silver; Spin glasses; Spin liquid; Spin-orbit interactions
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.123.237203

Kitaev magnets are materials with bond-dependent Ising interactions between localized spins on a honeycomb lattice. Such interactions could lead to a quantum spin-liquid (QSL) ground state at zero temperature. Recent theoretical studies suggest two potential signatures of a QSL at finite temperatures, namely, a scaling behavior of thermodynamic quantities in the presence of quenched disorder, and a two-step release of the magnetic entropy. Here, we present both signatures in Ag3LiO6 which is synthesized from α−Li2IrO3 by replacing the interlayer Li atoms with Ag atoms. In addition, the dc susceptibility data confirm the absence of a long-range order, and the ac susceptibility data rule out a spin-glass transition. These observations suggest a closer proximity to the QSL in Ag3LiIr2O6 compared to its parent compound α−Li2IrO3 that orders at 15 K. We discuss an enhanced spin-orbit coupling due to a mixing between silver d and oxygen p orbitals as a potential underlying mechanism.