Electrical transport and magnetic properties of the misfit layer compound (LaS)1.14NbS2

Abstract

(LaS)1.14NbS2 is a misfit layer compound built of alternate double layers of LaS with La in square pyramidal coordination with sulphur and sandwiched with NbS2 as occurs in 2H-NbS2. The electrical transport properties and magnetic properties were determined using single crystals and powder compacts. The compound is a p-type metal (Hall coefficient RH and Seebeck coefficient positive) with a strong anisotropy of the electrical resistivity: rho perpendicular to c/ rho /sub //c/=5*10-5. The electrical transport properties are interpreted as being due to holes in 4d(z2) band of the NbS2 part of the structure. The 4d(z2) band which is half-filled in the case of 2H-NbS2 contains 0.12 hole/Nb atom. This corresponds to a donation of 0.88 electron/Nb atom from the LaS part, the charge of La being +2.8. The magnetic properties are interpreted as being due to the LaS part. In the temperature region 40-300 K the curve of reciprocal magnetic susceptibility (not corrected) against T is linear with a Curie constant C of 1.4*10-6 m3 K (mol La)-1 corresponding to 0.14 4f electron at La, 0.86 electron being donated to the 4d(z2) band of the NbS2 part. Down to 4 K there are no signs of superconductivity.