Regensburg 2002 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 12: Hauptvortrag

HL 12.1: Hauptvortrag

Dienstag, 12. März 2002, 09:30–10:15, H15

The composite fermion and its quantum fluids — •Jainendra Jain — Department of Physics, The Pennsylvania State University, 104 Davey Laboratory, University Park, PA 16802

When electrons in two dimensions are exposed to a strong magnetic field, they capture quantum mechanical vortices to transform into bizarre new particles called composite fermions. This talk will describe the dramatic chain of events, triggered by the discovery of the integral quantum Hall effect (von Klitzing, 1980), the fractional quantum Hall effect (Tsui, Stormer, Gossard, 1982), and the theory of the 1/3 effect (Laughlin, 1983), which led to the introduction of composite fermions in 1989. The existence of composite fermions was subsequently confirmed in numerous rigorous and not-trivial experimental and theoretical studies, which not only explained and unified the previously known facts, but also led to surprising new discoveries. I will discuss the collective, topological, and quantum mechanical character of composite fermions, their parameters, quantum numbers, and quantum fluids; in particular, two new phases of composite fermions predicted recently will be mentioned in which they either form stripes or pairs at certain even denominator fractions in the lowest Landau level.