Correlated Paramagnetism and Interplay of Magnetic and Phononic Degrees of Freedom in 3d-5d Coupled La2CuIrO6

Abstract

Conventional Paramagnetism - a state with finite magnetic moment per ion sans long range magnetic ordering, but with lowering temperature the moment on each ion picks up a particular direction, breaking rotational symmetry, and results into long range magnetic ordering. However, in systems with competing multiple degrees of freedom this conventional notion may easily breaks and results into short range correlation much above the global magnetic transition temperature. La2CuIrO6 with complex interplay of spins (s =1/2) on Cu site and pseudo-spin (j =1/2) on Ir site owing to strong spin-orbit coupling provides fertile ground to observe such correlated phenomena. By a comprehensive temperature dependent Raman study, we have shown the presence of such a correlated paramagnetic state in La2CuIrO6 much above the long range magnetic ordering temperature (TN ). Our observation of strong interactions of phonons, associated with Cu/Ir octahedra, with underlying magnetic degrees of freedom mirrored in the observed Fano asymmetry, which remarkably persists as high as ~ 3.5TN clearly signals the existence of correlated paramagnetism hence broken rotational symmetry. Our detailed analysis also reveals anomalous changes in the self-energy parameters of the phonon modes, i.e. mode frequencies and linewidth, below TN, providing a useful gauge for monitoring the strong coupling between phonons and magnetic degrees of freedom.

arXiv comment22 pages, 6 figures

References in corpus (29)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Correlated quantum phenomena in the strong spin-orbit regime
• Kitaev-Heisenberg Model on Honeycomb Lattice: Possible Exotic Phases in Iridium Oxides $A_2$IrO${}_3$
• Mott physics and band topology in materials with strong spin-orbit interaction
• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8
• Scattering Continuum and Possible Fractionalized Excitations in $\alpha$-RuCl${}_3$
• Bandwidth-Controlled Insulator-Metal Transition and Correlated Metallic State in 5$d$ Transition Metal Oxides Sr${}_{n+1}$Ir${}_n$O${}_{3n+1}$ ($n$=1, 2, and $\infty$)
• Topological insulators and metal-insulator transition in the pyrochlore iridates
• Na2IrO3 as a spin-orbit-assisted antiferromagnetic insulator with a 340 meV gap
• Probing spin correlations with phonons in the strongly frustrated magnet ZnCr2O4
• Novel magnetism of Ir5+ ions in the double perovskite Sr2YIrO6
• Spin-Orbit Integrated Ground State and Magnetic Anisotropy in Sr${}_2$IrO${}_4$
• Raman spectroscopic signature of fractionalized excitations in the harmonic-honeycomb iridates $\beta$- and $\gamma$-Li${}_2$IrO${}_3$
• Ba2YIrO6: A cubic double perovskite material with Ir5+ ions
• Magnetism and electronic structure of La2ZnIrO6 and La2MgIrO6: candidate Jeff =1/2 Mott insulators
• Two-magnon Raman scattering and pseudospin-lattice interactions in Sr2IrO4 and Sr3Ir2O7
• Magnetism and spin-orbit coupling in Ir-based double perovskites La${}_{(}2-x$Sr${}_x$CoIrO${}_6$
• Giant spin-phonon-electronic coupling in a 5d oxide
• Effective magnetic interactions in spin-orbit coupled $d^4$ Mott insulators
• Coupled Phonons, Magnetic Excitations and Ferroelectricity in AlFeO3: Raman and First-principles Studies
• Non-collinear antiferromagnetism of coupled spins and pseudospins in the double perovskite La2CuIrO6
• Jahn-Teller effect in systems with strong on-site spin-orbit coupling
• Soft tilt and rotational modes in the hybrid improper ferroelectric Ca${}_3$Mn${}_2$O${}_7$
• Anisotropic interactions opposing magnetocrystalline anisotropy in Sr${}_3$NiIrO${}_6$
• Quantum criticality in the coupled two-leg spin ladder Ba2CuTeO6
• Superconducting Fluctuations and Anomalous Phonon Renormalization much above superconducting transition temperature in Ca4Al2O5.7Fe2As2
• Temperature-Dependent Infrared Reflectivity Studies of Multiferroic TbMnO_{3}: Evidence for Spin-Phonon Coupling

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