Electron effective mass in n-type electron-induced ferromagnetic semiconductor (In,Fe)As: Evidence of conduction band transport

The electron effective mass (m*) in n-type carrier-induced ferromagnetic semiconductor (In,Fe)As was estimated by using the thermoelectric Seebeck effect. It was found that m* is 0.03 ∼ 0.17m0 depending on the electron concentration, where m0 is the free electron mass. These values are similar to those of electrons in the conduction band of n+ InAs. The Fermi level EF in (In,Fe)As is located at least 0.15 eV above the conduction band bottom. Our results indicate that electron carriers in (In,Fe)As reside in the conduction band, rather than in a hypothetical Fe-related itinerant impurity band.