A $j_\mathrm{eff} = 1/2$ pseudospinon continuum in CaIrO$_3$

TL;DR

This paper reports the observation of a $j_ ext{eff} = 1/2$ pseudospinon continuum in CaIrO$_3$, revealing quasi-one-dimensional magnetic behavior in a three-dimensional crystal structure through RIXS measurements and theoretical modeling.

Contribution

It demonstrates the presence of a $j_ ext{eff} = 1/2$ pseudospinon continuum in CaIrO$_3$, highlighting the emergence of quasi-1D magnetism due to bond-dependent magnetic interactions.

Findings

Observation of a $j_ ext{eff} = 1/2$ pseudospinon continuum in CaIrO$_3$

Spectral agreement with weakly coupled spin-1/2 chain models

Identification of bond-dependent magnetic interactions as the origin

Abstract

In so-called $j_\mathrm{eff} = 1/2$ systems, including some iridates and ruthenates, the coherent superposition of $t_\mathrm{2g}$ orbitals in the ground state gives rise to hopping processes that strongly depend on the bond geometry. Resonant inelastic x-ray scattering (RIXS) measurements on CaIrO$_3$ reveal a prototypical $j_\mathrm{eff} = 1/2$ pseudospinon continuum, a hallmark of one-dimensional (1D) magnetic systems despite its three-dimensional crystal structure. The experimental spectra compare very well to the calculated magnetic dynamical structure factor of weakly coupled spin-1/2 chains. We attribute the onset of such quasi-1D magnetism to the fundamental difference in the magnetic interactions between the $j_\mathrm{eff} = 1/2$ pseudospins along the corner- and edge-sharing bonds in CaIrO$_3$.