We report on a giant negative magnetoresistance in very high mobility GaAs/AlGaAs heterostructures and quantum wells. The effect is the strongest at B1 kG, where the magnetoresistivity develops a minimum emerging at T2 K. Unlike the zero-field resistivity which saturates at T2 K, the resistivity at this minimum continues to drop at an accelerated rate to much lower temperatures and becomes several times smaller than the zero-field resistivity. Unexpectedly, we also find that the effect is destroyed not only by increasing temperature but also by modest in-plane magnetic fields. The analysis shows that giant negative magnetoresistance cannot be explained by existing theories considering interaction-induced or disorder-induced corrections.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Feb 6 2012|