Kitaev spin liquid in the Co-based honeycomb system BaCo2(P0.85V0.15)2O8

The newly reported compound BaCo2(P1-xVx)2O8 fulfills the necessary condition for hosting the Kitaev-type interactions. In particular, for the x=0.15 composition, the dc and ac magnetic susceptibility results show a substantial enhancement below 100 K and a spin-glass ground state through Tg ~ 5 K. Given the small Curie-Weiss temperature (-3.2 K) relative to an energy scale of Tg, the antiferromagnetic Heisenberg and ferromagnetic Kitaev interactions are present. Thermodynamic measurements show that the application of an external field enhances quantum fluctuations. All the previous experimental results suggest that the structural geometry, chemical disorder, and external field cooperatively promote a Kitaev QSL-like state. In this project, we aim at performing ZF- and LF-muSR experiments on BaCo2(P0.85V0.15)2O8 to test a proximity to a Kitaev spin liquid.