1211.6228 (Kensaku Chida et al.)

Observation of finite excess noise in the voltage-biased quantum Hall
regime as a precursor for breakdown    [PDF]

Kensaku Chida, Tomonori Arakawa, Sadashige Matsuo, Yoshitaka Nishihara, Takahiro Tanaka, Daichi Chiba, Teruo Ono, Tokuro Hata, Kensuke Kobayashi, Tomoki Machida

We performed noise measurements in a two-dimensional electron gas to investigate the nonequilibrium quantum Hall effect (QHE) state. While excess noise is perfectly suppressed around the zero-biased QHE state reflecting the dissipationless electron transport of the QHE state, considerable finite excess noise is observed in the breakdown regime of the QHE. The noise temperature deduced from the excess noise is found to be of the same order as the energy gap between the highest occupied Landau level and the lowest empty one, supporting the idea that avalanche-type electron heating occurs. Moreover, unexpected finite excess noise is observed at a finite source-drain bias voltage smaller than the onset voltage of the QHE breakdown, which may be called the "precursor regime." The excess noise in this precursor regime is reproducibly observed at different filling factors and cooling downs. In addition, it shows unique temporal variation on a time scale of ten minutes. Such a slow dynamics of the excess noise in the precursor regime is proposed to originate from the electron tunneling between the edge states and the localized bulk states.

View original: http://arxiv.org/abs/1211.6228