NMR study of the charge-density-wave state in VSe2

The 51V NMR lineshape, Knight shift, quadrupole interaction, spin-lattice relaxation time and magnetic susceptibility in a single-crystalline VSe2 are studied in the temperature range 4.2 to 300 K. Above the charge-density-wave (CDW) onset temperature T0 approximately 110 K the linear temperature dependence of the quadrupole coupling constant and the pretransitional line broadening are found. The temperature dependence of the CDW amplitude is determined from the width of electric-field-gradient distribution at nuclear sites below T0. Combining the experimental data on NMR properties and magnetic susceptibility the effective electron-electron interaction parameter, J = 0.29 eV, is estimated and the density of electron states at the Fermi level. The latter is found to decrease from 2.05 to 1.60 states/eV spin V at the phase transition into the CDW state. (author)