Phase transitions and symmetry breaking in disordered quantum Hall edge states

Tunneling into the edge of a quantum Hall droplet is a sensitive probe of the topological orders believed to exist in fractional quantum Hall states. The tunneling behavior of a general hierarchy state is studied within the chiral-Luttinger-liquid model of low-energy edge dynamics. Adding random hopping of quasiparticles between edge modes results in "symmetry restoration by disorder" and universal weak tunneling behavior in edges with modes traveling in both directions. We develop a boost coordinate technique and apply it to find the edge phases and tunneling exponents of all topologically stable principal hierarchy states. States with neutral modes in both directions along the edge have multiple stable fixed points which can be classified by their symmetries. When the tunneling current into an edge is large, the system can cross over from the weak-tunneling fixed point to a different strongly coupled fixed point with different conductance and effective charge. Edges with multiple modes can have multiple strongly coupled fixed points. We develop a general formalism to analyze weakly and strongly coupled fixed points of point tunneling. Adding interactions to tunneling between two Laughlin edges is shown to lead to a continuous variation of effective quasiparticle charge and conductance with interaction strength.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Moore, Joel Ellis, 1973-

Advisor dc:contributor.advisor

• Xiao-Gang Wen.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8281

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8281