https://doi.org/10.1007/s100510170298
CPA density of states and conductivity in a double-exchange system containing impurities
1
Department of Electrical and Computer Engineering,
Ben-Gurion University of the Negev POB 653, Beer-Sheva 84105, Israel
2
Jack and Pearl Resnick Institute of Advanced Technology,
Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
Corresponding author: a kogan@quantum.ph.biu.ac.il
Received:
13
June
2000
Revised:
5
January
2001
Published online: 15 February 2001
We study density of states and conductivity of the doped double-exchange system, treating interaction of charge carriers both with the localized spins and with the impurities in the coherent potential approximation. It is shown that under appropriate conditions there is a gap between the conduction band and the impurity band in paramagnetic phase, while the density of states is gapless in ferromagnetic phase. This can explain metal-insulator transition frequently observed in manganites and magnetic semiconductors. Activated conductivity in the insulator phase is numerically calculated.
PACS: 75.50.Pp – Magnetic semiconductors / 75.30.Vn – Colossal magnetoresistance / 72.10.-d – Theory of electronic transport; scattering mechanisms
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001