Volume 80, Number 1, October 2007
Article Number 17003
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 07 September 2007
EPL, 80 (2007) 17003
DOI: 10.1209/0295-5075/80/17003

On transport in quantum Hall systems with constrictions

S. Lal

The Abdus Salam ICTP - Strada Costiera 11, Trieste 34014, Italy

received 19 February 2007; accepted in final form 13 August 2007; published October 2007
published online 7 September 2007

We study edge transport in a simple model of a constricted quantum Hall system with a lowered local filling factor. The current backscattered from the constriction is explained from a matching of the properties of the edge-current excitations in the constriction ($\nu _{2}$) and bulk ($\nu _{1}$) regions. We develop a hydrodynamic theory for bosonic edge modes inspired by this model, finding that a competition between two tunneling process, related by a quasiparticle-quasihole symmetry, determines the fate of the low-bias transmission conductance. A novel generalisation of the Kane-Fisher quantum impurity model is found, describing transitions from a weak-coupling theory at partial transmission to strong-coupling theories for perfect transmission and reflection as well as a new symmetry dictated fixed point. These results provide satisfactory explanations for recent experimental results at filling factors of 1/3 and 1.

73.23.-b - Electronic transport in mesoscopic systems.
71.10.Pm - Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.).
73.43.Jn - Tunneling.

© Europhysics Letters Association 2007