Fractional Quantum Hall Effect at Landau Level Filling nu=4/11

TL;DR

This study reports the observation of the fractional quantum Hall effect at filling factor 4/11, demonstrating quantized Hall resistance and an energy gap at very low temperatures in high mobility samples.

Contribution

First experimental evidence of fractional quantum Hall effect at nu=4/11 with detailed transport measurements at ultra-low temperatures.

Findings

Quantized Hall resistance within 1% of expected value

Activation energy gap of approximately 7 mK

Observation of developing Hall plateaus at neighboring states

Abstract

We report low temperature electronic transport results on the fractional quantum Hall effect of composite fermions at Landau level filling nu = 4/11 in a very high mobility and low density sample. Measurements were carried out at temperatures down to 15mK, where an activated magnetoresistance Rxx and a quantized Hall resistance Rxy, within 1% of the expected value of h/(4/11)e^2, were observed. The temperature dependence of the Rxx minimum at 4/11 yields an activation energy gap of ~ 7 mK. Developing Hall plateaus were also observed at the neighboring states at nu = 3/8 and 5/13.