Charge and spin density distribution in VSe2 dichalcogenide according to NMR 51V data

A polycrystalline sample of VSe2 was studied using magnetometry and nuclear magnetic resonance (NMR) spectroscopy on 51V nuclei. The values of the components of the magnetic shift tensors and the electric field gradient (EFG) at the location of vanadium nuclei were determined from the processing of the NMR spectra recorded in the range from 300 K to 10 K. It was found that the valence contribution to the EFG is opposite to the lattice contribution. At temperatures below T0 ≈ 110 K, the 51V NMR line undergoes significant inhomogeneous broadening, which is associated with a transition to a state with a charge density wave (CDW). From the data on the 51V NMR line broadening, changes in the quadrupole frequency nQ across the crystal were determined, which is a characteristic of the charge density distribution near the 51V nuclei. A combined analysis of the temperature dependences of the NMR line shift and magnetic susceptibility allowed us to estimate the hyperfine magnetic fields on vanadium nuclei in VSe2 in the CDW state. An estimate was obtained for the difference in spin polarization of various 3d-orbitals of the V ion, which corresponds to the density of electron states with an energy slightly below the Fermi level.