Magnetoresistance of Si(001) MOSFETs with high concentration of electrons

TL;DR

This paper investigates electron transport in high-mobility Si(001) MOSFETs with high electron concentration, revealing novel oscillations linked to excited subband occupation, negative magnetoresistance, and nonlinear Hall effects.

Contribution

It reports the first observation of additional oscillations due to excited subband occupation in Si(001) MOSFETs and analyzes their impact on magnetoresistance and Hall resistance.

Findings

Observation of additional oscillations linked to excited subbands.

Detection of strong negative magnetoresistance.

Nonlinear field dependence of Hall resistance at high carrier densities.

Abstract

We present an experimental study of electron transport in inversion layers of high-mobility Si(001) samples with occupied excited subbands. The second series of oscillations, observed in addition to the main series of Shubnikov-de Hass oscillations, is tentatively attributed to the occupation of a subband associated with the $E_{0'}$ level. Besides, a strong negative magnetoresistance and nonlinear field dependence of the Hall resistance accompany the novel oscillations at high carrier concentrations. The heating of the 2D electron layers leads to suppression of the observed anomalies.