The Mechanism of the Appearance of an Electromotive Force on Heating of SmS Single Crystals

V. V. Kaminskiy, L. N. Vasil'ev, M. V. Romanova, and S. M. Solov'ev

Ioffe Physicotechnical Institute, Russian Academy of Sciences, Politekhnicheskaya ul. 26, St. Petersburg, 194021 Russia

Received November 16, 2000

Abstract-We analyze the experimental variation of the concentration of conduction electrons in semiconduct­ing SmS single crystals with increasing temperature within a shallow-impurity model. It is shown that the appearance of an electromotive force is due to accumulation of the critical concentration of free electrons, which results in screening of the Coulomb potential of Sm²⁺ impurity ions that are responsible for the creation of donor levels with an activation energy of 0.045 eV in the band gap of SmS single crystals. © 2001 MAIK "Nauka/Interperiodica".

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