Effective Mass and Land´e g-factor in Si-MOSFETs near the Critical Density

• Published in: Journal of the Korean Physical Society 2014, 64(3), , pp.424-428
• Main Authors: Lhoussine Limouny, Abdelhamid El kaaouachi, Chi-Te Liang
• Format: Article
• Language: English
• Subjects: 물리학
• ISSN: 0374-4884; 1976-8524

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 appliedparallel to the plane of the 2DEG, a signature of complete spin polarization, as evidenced by thesaturation of the resistivity, is observed. We measured the effective mass and the Land´e g-factornear the metal-insulator transition (MIT) and found that the Land´e g-factor remained almostconstant and close to its value in bulk silicon. In contrast, we have observed a sharp increase inthe effective mass near the critical density of the MIT. Our new results suggest that the sharpincrease 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 spinpolarized2DEG. The data indicate that electron-electron interactions strongly modify the effectivemass 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, vanishesat a characteristic density n higher than the critical density nc of the MIT. This is in contrastto the existing experimental results, and further studies are required if this discrepancy is to beunderstood. KCI Citation Count: 0