Notes

Outline

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