Effective mass and Landé g-factor in Si-MOSFETs near the critical density

Autor: L. Limouny, Chi-Te Liang, Abdelhamid El Kaaouachi
Rok vydání: 2014
Předmět:
Zdroj: Journal of the Korean Physical Society. 64:424-428
ISSN: 1976-8524
0374-4884
DOI: 10.3938/jkps.64.424
Popis: We analyze the electrical resistivity and conductivity of a dilute two-dimensional electron gas (2DEG) in a Si metal-oxide-semiconductor field-effect transistor. When a magnetic field is applied parallel to the plane of the 2DEG, a signature of complete spin polarization, as evidenced by the saturation of the resistivity, is observed. We measured the effective mass and the Lande g-factor near the metal-insulator transition (MIT) and found that the Lande g-factor remained almost constant and close to its value in bulk silicon. In contrast, we have observed a sharp increase in the effective mass near the critical density of the MIT. Our new results suggest that the sharp increase in the previously-observed spin susceptibility is mainly due to the enhanced effective mass. Therefore, renormalization of the effective mass could play an important role in a dilute spinpolarized 2DEG. The data indicate that electron-electron interactions strongly modify the effective mass but only weakly affect the g-factor in a dilute 2DEG. Moreover, our results indicate that Bc, which corresponds to the magnetic field at which the magnetoresistivity reaches saturation, vanishes at a characteristic density nχ higher than the critical density nc of the MIT. This is in contrast to the existing experimental results, and further studies are required if this discrepancy is to be understood.
Databáze: OpenAIRE
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