ELECTRONIC-PROPERTIES AND BAND-STRUCTURE OF IRSE2

Transport coefficient measurements (DC conductivity and thermoelectric power) were performed on compacted bars of polycrystalline IrSe2 in the 100-570 K temperature range. The experimental results are interpreted on the basis of an n-type compensated semiconductor model. At low temperatures, a narrow band which originates from non-stoichiometry mainly participates in the conduction by thermally activated hopping of small polarons. The charge balance adopted by anionic groups is discussed. The schematic band model which is retained takes into account all the transport properties and the ion charge balance Ir3+Se2-(Se2)1/2(2-). Moreover, IrSe2 has recently been shown to function as a cathode material in lithium batteries.