*

CoNb₂O₆, a twisted Kitaev chain, is a promising candidate for observing transverse field Ising chain (TFIC)-like low-energy 1D excitations [1]. The low energy excitations of a TFIC are hypothesized to be topologically-protected fractionalized spin-1/2 quasiparticles, often called ‘spinons’. Spinons must always be excited in pairs and there are many ways to deposit energy and momentum into two particles; this leads to a broad absorption continuum that hides most of the information about spinon lifetimes and lineshapes. Recent theory has predicted that detection of spinon echoes could enable determination of these properties [2]. UCSB's free electron laser-powered pulsed electron magnetic resonance spectrometer has been used to measure spin echoes in various paramagnetic systems at 240 GHz [3,4] and is uniquely positioned to detect spinon echoes. We will present our progress toward measuring spinon echoes in CoNb₂O₆, from which we are currently able to place an upper bound on spinon lifetimes.

[1] C. M. Morris et. al., Nat. Phys. (2021).

[2] Y. Wan and N. P. Armitage, Phys. Rev. Lett. (2019).

[3] S. Takahashi et. al., Nature (2012).

[4] M. Fataftah, et. al., JACS (2020).