Quantum-Hall Insulator
Transition
Angus MacKinnon
Blackett Laboratory, Imperial College
 London SW7 2BW, UK
Oct. 01 – Sep. 02: Cavendish Laboratory
Madingley Rd, Cambridge, UK

A Phase Transition
Low Disorder – Quantum Hall Effect
High Disorder – Insulator
How does the transition happen?
Levitation?
Some other mechanism?
Acknowledgement: James Dynes

Trivial Levitation

Conductivity Flow

Resistivity Flow

Density of States
&
Localisation Length

Method
Calculate
Green’s Function Recursion
Landauer Geometry

Preliminary Results

Preliminary Results (b)

Conclusions
Hall Conductivity falls in steps, but is not quantised.
Higher plateaux fall first.
No sign of movement of the transition region.
Levitation – 1
Something else – 2 & 3