Interplay of magnetism and dimerization in pressurized Kitaev material $\beta$-Li${}_2$IrO${}_3$

Abstract

We present magnetization measurements on polycrystalline $\beta$-Li${}_2$IrO${}_3$ under hydrostatic pressures up to 3~GPa and construct the temperature-pressure phase diagram of this material. Our data confirm that magnetic order breaks down in a first-order phase transition at $p_{\mathrm{c}}$ $\approx$ 1.4~GPa and additionally reveal a step-like feature -- magnetic signature of structural dimerization -- that appears at $p_{\mathrm{c}}$ and shifts to higher temperatures upon further compression. Following the structural study by L. S. I. Veiga et al. [Phys. Rev. B 100, 064104 (2019)], we suggest that a partially dimerized phase with a mixture of magnetic and non-magnetic Ir${}^{4+}$ sites develops above $p_{\mathrm{c}}$. This phase is thermodynamically stable between 1.7 and 2.7~GPa according to our ab initio calculations. It confines the magnetic Ir${}^{4+}$ sites to weakly coupled tetramers with a singlet ground state and no long-range magnetic order. Our results rule out the formation of a pressure-induced spin-liquid phase in $\beta$-Li${}_2$IrO${}_3$ and reveal peculiarities of the magnetism collapse transition in a Kitaev material. We also show that a compressive strain imposed by the pressure treatment of $\beta$-Li${}_2$IrO${}_3$ enhances signatures of the 100~K magnetic anomaly at ambient pressure.

arXiv comment10 pages, 10 figures

References in corpus (31)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Kitaev quantum spin liquid - concept and materialization
• Generic spin model for the honeycomb iridates beyond the Kitaev limit
• Models and Materials for Generalized Kitaev Magnetism
• Challenges in Design of Kitaev Materials: Magnetic Interactions from Competing Energy Scales
• Physics of the Kitaev model: fractionalization, dynamical correlations, and material connections
• Hyper-honeycomb iridate $\beta$-Li2IrO3 as a platform for Kitaev magnetism
• Unconventional magnetic order on the hyperhoneycomb Kitaev lattice in $\beta$-Li2IrO3: full solution via magnetic resonant x-ray diffraction
• Pressure-induced dimerization and valence bond crystal formation in the Kitaev-Heisenberg magnet alpha-RuCl3
• Competition between spin-orbit coupling, magnetism, and dimerization in the honeycomb iridates: $\alpha$-Li${}_2$IrO${}_3$ under pressure
• Breakdown of magnetic order in the pressurized Kitaev iridate $\beta$-Li${}_2$IrO${}_3$
• Pressure-tuned magnetic interactions in honeycomb Kitaev materials
• High-pressure magnetization and NMR studies on $\alpha$-RuCl${}_3$
• Field-induced intertwined orders in 3D Mott-Kitaev honeycomb $\beta$-Li2IrO3
• Pressure-tuning of bond-directional exchange interactions and magnetic frustration in hyperhoneycomb iridate $\beta$-$\mathrm{L}{\mathrm{i}}_2\mathrm{Ir}{\mathrm{O}}_3$
• Detuning the Honeycomb of $\alpha$-RuCl${}_3$: Pressure-Dependent Optical Studies Reveal Broken Symmetry
• Raman evidence for dimerization and Mott collapse in $\alpha$-RuCl${}_3$ under pressures
• Pressure-driven collapse of the relativistic electronic ground state in a honeycomb iridate
• Pressure-induced collapse of spin-orbital Mott state in the hyperhoneycomb iridate $\beta$-Li${}_2$IrO${}_3$
• Revealing frustrated local moment model for pressurized hyperhoneycomb iridate: paving a way toward quantum spin liquid
• Magnetic field-induced evolution of intertwined orders in the Kitaev magnet $\beta$-Li${}_2$IrO${}_3$
• Kitaev magnetism through the prism of lithium iridate
• Pressure-induced structural dimerization in the hyperhoneycomb iridate $\beta$-Li${}_2$IrO${}_3$ at low temperatures
• Anisotropic temperature-field phase diagram of single-crystalline $\beta$-Li${}_2$IrO${}_3$: magnetization, specific heat, and ${}^7$Li NMR study
• Optical signature of the pressure-induced dimerization in the honeycomb iridate $\alpha$-Li${}_2$IrO${}_3$
• Field evolution of low-energy excitations in the hyperhoneycomb magnet $\beta$-Li${}_2$IrO${}_3$
• Resonant inelastic x-ray scattering spectra in the hyperhoneycomb iridate $\beta$-Li${}_2$IrO${}_3$: First principles calculations
• Hidden spin-orbital order in the Kitaev hyperhoneycomb $\beta$-Li${}_2$IrO${}_3$
• Lattice dynamics and structural transition of the hyperhoneycomb iridate $\beta$-Li${}_2$IrO${}_3$ investigated by high-pressure Raman scattering

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