Nonequilibrated Counterpropagating Edge Modes in the Fractional Quantum Hall Regime

作者：Grivnin Anna^*; Inoue Hiroyuki; Ronen Yuval; Baum Yuval; Heiblum Moty; Umansky Vladimir; Mahalu Diana

来源：Physical Review Letters, 2014, 113(26): 266803.

DOI：10.1103/PhysRevLett.113.266803

It is well established that density reconstruction at the edge of a two-dimensional electron gas takes place for hole-conjugate states in the fractional quantum Hall effect (such as v = 2/3, 3/5, etc.). Such reconstruction leads, after equilibration between counterpropagating edge channels, to a downstream chiral current edge mode accompanied by upstream chiral neutral modes (carrying energy without net charge). Short equilibration length prevented thus far observation of the counterpropagating current channels-the hallmark of density reconstruction. Here, we provide evidence for such nonequilibrated counterpropagating current channels, in short regions (l = 4 mu m and l = 0.4 mu m) of fractional filling v = 2/3 and, unexpectedly, v = 1/3, sandwiched between two regions of integer filling v = 1. Rather than a two-terminal fractional conductance, the conductance exhibited a significant ascension towards unity quantum conductance (G(Q) = e(2)/h) at or near the fractional plateaus. We attribute this conductance rise to the presence of a nonequilibrated channel in the fractional short regions.

• 出版日期2014-12-22