Topological states of matter – from the quantum Hall effect to Majorana fermions Ady Stern (Weizmann) The quantum Hall effects – introduction Unavoidable conclusions
The quantum Hall effects Introduction
Landau level filling factor = density of electrons The Hall effect I B +++++++++++++++ --------------------------------- Electrons in two dimensions Classically, Hall resistivity - longitudinal resistivity - unchanged by B. Quantum mechanically degenerate harmonic oscillator spectrum Landau levels Landau level filling factor = density of electrons density of flux quanta
The quantum Hall effect zero longitudinal resistivity - no dissipation quantized Hall resistivity to amazing precision Integer quantum Hall effect - integer n Fractional quantum Hall effect
Single particle spectrum – highly degenerate Landau levels
The original sample of the FQHE: