Phys. Rev. B 87, 245406 (2013) [9 pages]Origins of conductance anomalies in a p-type GaAs quantum point contactAbstract
Received 23 January 2013; published 4 June 2013 Low-temperature transport measurements on a p-GaAs quantum point contact are presented which reveal the presence of a conductance anomaly that is markedly different from the conventional “0.7 anomaly.” A lateral shift by asymmetric gating of the conducting channel is utilized to identify and separate different conductance anomalies of local and generic origins experimentally. While the more generic 0.7 anomaly is not directly affected by changing the gate configuration, a model is proposed which attributes the additional conductance features to a gate-dependent coupling of the propagating states to localized states emerging due to a nearby potential imperfection. Finite bias conductivity measurements reveal the interplay between the two anomalies consistently with a two-impurity Kondo model. ©2013 American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.87.245406
DOI:
10.1103/PhysRevB.87.245406
PACS:
73.23.-b, 73.63.-b
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