Frustration enhanced by Kitaev exchange in a $\boldsymbol{\tilde{j}_{\text{eff}}=\frac12}$ triangular antiferromagnet

Thermal conductivity of triangular-lattice antiferromagnet Na2BaCo(PO4)2: Absence of itinerant fermionic excitations

“…2(a), giving the effective moment of a Co 2+ ion at low temperature being 4.32 µ B and the in-trinsic spin-1/2 exchange Curie-Weiss temperature θ = −3.18 K. The g factor of 4.99 deduced thereout is close to the magnetization and electron spin resonance results in Ref. [27]. Assuming Na 2 BaCo(PO 4 ) 2 satisfies the XXZ model like YbMgGaO 4 [28], we obtain the exchange interaction J zz = −2θ/3 = 2.12 K. Field dependence of magnetization at T = 2 K is plotted in Fig.…”

“…As mentioned above, this result is a strong evidence for the existence of itinerant gapless spinons [21][22][23][24], making Na 2 BaCo(PO 4 ) 2 different from the rest of QSL and QSL-like candidates. Based on this work, theoretical calculations revealed that the anisotropic ferromagnetic Kitaev exchange plays an important role in assisting the realization of this QSL-like state above T N [27]. Since the issue of detecting spinons is the foundation for understanding the nature of QSL states, it is necessary to revisit these thermodynamic and heat transport properties of Na 2 BaCo(PO 4 ) 2 .…”