Absence of long-range magnetic order in Fe1−δTe2 (δ ≈ 0.1) crystals

Transition metal dichalcogenides attract considerable attention due to a variety of interesting properties, including long-range magnetism in nanocrystals. Here we investigate the magnetic, thermal, and electrical properties of an FeTe2 single crystal with iron vacancy defects. Magnetic measurements show a paramagnetic state and the absence of magnetic order with low anisotropy in the magnetic susceptibility. Fe 3d orbitals are well hybridized, contributing to the bad metal electrical resistivity. Observed thermal conductivity values below room temperature are rather low and comparable to those of high-performance thermoelectric materials. Our results indicate that FeTe2 can form in a highly defective marcasite crystal structure which can be exploited in future materials design.