Spinons and damped phonons in spin-1/2 quantum-liquid Ba${}_4$Ir${}_3$O${}_{10}$ observed by Raman scattering

Abstract

In spin-1/2 Mott insulators, non-magnetic quantum liquid phases are often argued to arise when the system shows no magnetic ordering, but identifying positive signatures of these phases or related spinon quasiparticles can be elusive. Here we use Raman scattering to provide three signatures for spinons in a possible spin-orbit quantum liquid material Ba${}_4$Ir${}_3$O${}_{10}$: (1) A broad hump, which we show can arise from Luttinger Liquid spinons in Raman with parallel photon polarizations normal to 1D chains; (2) Strong phonon damping from phonon-spin coupling via the spin-orbit interaction; and (3) the absence of (1) and (2) in the magnetically ordered phase that is produced when 2% of Ba is substituted by Sr ((Ba${}_{0.98}$Sr${}_{0.02}$)${}_4$Ir${}_3$O${}_{10}$). The phonon damping via itinerant spinons seen in this quantum-liquid insulator suggests a new mechanism for enhancing thermoelectricity in strongly correlated conductors, through a neutral quantum liquid that need not affect electronic transport.

References in corpus (1)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models

Cited by in corpus (5)

• Emergence of spinons in layered trimer iridate Ba4Ir3O10
• Magnon, doublon and quarton excitations in 2D S=1/2 trimerized Heisenberg models
• Magnetization Plateaus in the Two-dimensional S = 1/2 Heisenberg Model with a 3$\times$3 Checkerboard Structure
• Spinon excitations and spin correlations in the one-dimensional quantum magnet $\beta$-VOSO${}_4$ probed by Raman spectroscopy
• Phonon anomalies and critical scaling in the spin-$1/2$ trimer chain Na${}_2$Cu${}_3$Ge${}_4$O${}_{12}$