Weak localization and Mott state in two-dimensional Sr3V5S11

Abstract

We report on the high-pressure synthesis, structural study and physical properties of a new layered compound, Sr3V5S11. Single-crystals of ∼0.3 mm size were synthesized at the optimized growth conditions of 6 GPa and 1600 ° C. The refinement of x-ray diffraction data indicates that the crystal structure is monoclinic (space group C2/c), with cell parameters a = 8.7165(7) Å, b = 15.1096(13) Å, c = 23.111(2) Å, and β = 98.734(9). The structure consists of a stacking of VS2 layers with a CdI2-type structure within the ab-plane connected by trimers of face-sharing VS6 octahedra oriented along the out-of-plane direction. Salient features are a 4 + valence of the V ions in the planes and a 3 + valence in the trimers and a large stripe-like modulation of the V–V distances in the planes leading to quasi-one-dimensional properties. The magnetic susceptibility displays a large temperature-independent contribution, χ0, in addition to a moderate Curie–Weiss term. In the 300–120 K range, the electrical resistivity is described well by a semiconducting-like behaviour with a room-temperature value of ∼1.2–10 mΩ cm and a modest activation energy of ∼13.5 meV. At lower temperatures, a crossover to a one-dimensional variable range hopping regime is observed, supporting a scenario of a correlated 1D system.