Evidences for the random singlet phase in a new honeycomb iridate SrIr${}_2$O${}_{6-\delta }$

Abstract

Strong spin-orbital-coupling magnetic systems with the honeycomb structure can provide bond-directional interactions which may result in Kitaev quantum spin liquids and exotic anyonic excitations. However, one of the key ingredients in real materials$-$disorders$-$has been much less studied in Kitaev systems. Here we synthesized a trigonal SrIr${}_2$O${}_{6-\delta }$ with $\delta \approx 0.25$, which consists of two-dimensional honeycomb Ir planes with edge-sharing IrO${}_6$ octahedra. First-principles computation and experimental measurements suggest that the electronic system is gapped, and there should be no magnetic moment as the Ir${}^{5+}$ ion has no unpaired electrons. However, significant magnetism has been observed in the material, and it can be attributed to disorders that are most likely from oxygen vacancies. No magnetic order is found down to 0.05 K, and the low-temperature magnetic properties exhibit power-law behaviors in magnetic susceptibility and zero-field specific heat, and a single-parameter scaling of the specific heat under magnetic fields. These results provide strong evidence for the existence of the random singlet phase in SrIr${}_2$O${}_{6-\delta }$, which offers a different member to the family of spin-orbital entangled iridates and Kitaev materials.

6 pages, 4 figures

References in corpus (10)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Exact results for spin dynamics and fractionization in the Kitaev Model
• Topological characterization of quantum phase transitions in a S=1/2 spin model
• Hyper-honeycomb iridate $\beta$-Li2IrO3 as a platform for Kitaev magnetism
• Long range magnetic ordering in Na${}_2$IrO${}_3$
• Magnetic Excitations and Continuum of a Field-Induced Quantum Spin Liquid in $\alpha$-RuCl${}_3$
• Thermodynamic Evidence of Proximity to a Kitaev Spin-Liquid in Ag${}_3$LiIr${}_2$O${}_6$
• Disorder upon disorder: localization effects in the Kitaev spin liquid
• Effect of structural disorder on the Kitaev magnet Ag${}_3$LiIr${}_2$O${}_6$

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• In-plane anisotropic response to the uniaxial pressure in the hidden order state of URu${}_2$Si${}_2$
• Possible realization of a randomness-driven quantum disordered state in an S = 1/2 antiferromagnet Sr3CuTa2O9
• Scaling and data collapse of two-dimensional random singlet state in magnetic field
• Fluctuation-induced first order phase transitions in Kitaev-like $d^4$ honeycomb magnet
• Finite Spinon Density-of-States in Triangular-Lattice Delafossite TlYbSe${}_2$