Size-dependent giant-magnetoresistance in millimeter scale GaAs/AlGaAs 2D electron devices

作者：Mani R G^*; Kriisa A; Wegscheider W

来源：Scientific Reports, 2013, 3(1): 2747.

DOI：10.1038/srep02747

Large changes in the electrical resistance induced by the application of a small magnetic field are potentially useful for device-applications. Such Giant Magneto-Resistance (GMR) effects also provide new insights into the physical phenomena involved in the associated electronic transport. This study examines a %26quot;bell-shape%26apos;%26apos; negative GMR that grows in magnitude with decreasing temperatures in mm-wide devices fabricated from the high-mobility GaAs/AlGaAs 2-Dimensional Electron System (2DES). Experiments show that the span of this magnetoresistance on the magnetic-field-axis increases with decreasing device width, W, while there is no concurrent Hall resistance, R-xy, correction. A multi-conduction model, including negative diagonal-conductivity, and non-vanishing off-diagonal conductivity, reproduces experimental observations. The results suggest that a size effect in the mm-wide 2DES with mm-scale electron mean-free-paths is responsible for the observed %26quot;non-ohmic%26apos;%26apos; size-dependent negative GMR.

• 出版日期2013-9-25