Statistical Analysis of Magnetoconductance in a Mesoscopic 2DEG
Abstract
We report statistical analysis of the low-temperature conductance in a wide and short two-dimensional electron gas (2DEG) as its chemical potential and the applied magnetic field are changed. The 2DEG is realized in Si MOSFETs with lengths of the order of a few μm. The chemical potential is varied from strongly insulating (conductance per square σ ~ 10-4 e^2/h) into metallic regime (σ ~ 0.5 e^2/h). A perpendicular magnetic field is applied from 0 up to 2 T. We find that the magnetic field dependence of the average conductance and of the statistics of conductance fluctuations, such as distribution functions, power spectra, and contour plots, changes as σ is varied. For example, the magnetoconductance (MC) is generally negative for B < 1T, but we observe a positive MC near a 2D metal-insulator transition (σ ~ 0.1-0.3 e^2/h). On the other hand, for B > 1T, MC changes sign from positive to negative as σ increases.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.G1308L