High-press. NMR
Frustration
Mott-Insulator
Spin liquid
Orbital order
■ Orbital-dependent local spin susceptibility
In strongly correlated electron system with orbital degrees of freedom, the spin correlation generally depends on orbital. The local spin susceptibility probed by NMR can resolve the orbital dependent behavior via the anisotropic Knight shift due to anisotropic hyperfine interactions between the nuclear spin and the 3d spins.Our main target materials are the vanadium oxides having orbital degrees of freedom and located on the verge of the metal-insulator transition. The quasi-one-dimensional K2V8O16 exhibits the metal-insulator transition at 160 K, where the magnetic susceptibility shows an incomplete drop. We found that the spin susceptibility was dominated by dxy in the paramagnetic metallic state and the nonmagnetic insulating phase, consistent with the orbital-assisted one-dimensionality [14]. We have also revealed the a1g character in the heavy Fermion LiV2O4 and the alg-eg' hybridization in V2O3.
References
"Metal-insulator transition in the hollandite K2V8O16 with a frustrated zigzag ladder probed by 51V NMR",
Physical Review B, 83, 155111 (2011).