Competing energy scales in a rhodium oxide spinel

Materials possessing frustrated crystal structures in conjunction with interacting spin, charge, and orbital degrees of freedom offer an avenue toward non-trivial quantum phenomenology. The spinel structure type is one that possesses frustration through its intertwined diamond and pyrochlore sublattices, and the spinel LiRh2O4 has been demonstrated to possess spin dimerization, charge ordering, and orbital ordering at tangible energy scales [1]. Furthermore, recent measurements of the local structure in this material indicate that the charge ordering arises from strong correlations and is similar to that of magnetite, satisfying the ‘Anderson condition’ for pyrochlore lattices [2]. In this talk, we will demonstrate the effect of electron and hole doping in the structural and physical properties of LiRh2O4, with an emphasis on the effect of dopants on the formation of dimers via changes in the local structure as indicated by pair distribution function measurements. Our results demonstrate an opportunity to study competing energy scales on a frustrated, mixed-valent pyrochlore lattice.

[1] Okamoto, et al., Phys. Rev. Lett. 101, 086404 (2008).

[2] Shiomi, et al., Phys. Rev. B 105, L041103 (2022).