Thermoelectric and Magnetic Properties of a Narrow-Gap Semiconductor FeGa₃

Abstract

We report transport, thermal, and magnetic measurements on single crystalline samples of FeGa 3 prepared by a Ga self flux method. The electrical resistivity and Hall coefficient at temperatures above 300 K display semiconducting behaviors with energy gaps of 0.47 and 0.54 eV, respectively, whose values agree with the calculated band gap. In the saturation range 100–260 K, the carrier mobility µ exhibits an unusual dependence on temperature; µ( T )∝ T -5/2 . The thermopower has a large negative minimum of -350 µV/K at 300 K. The diamagnetic susceptibility weakly depends on temperature, which confirms the absence of localized magnetic moments. The T -linear coefficient of the specific heat is 0.03 mJ/(K 2 ·mol), being two orders of magnitude smaller than that reported for Fe-based Kondo semiconductors FeSi and FeSb 2 .