Electron-electron interactions and metal-insulator transition in 2D

 Prof.dr. T.M. Klapwijk, Technical University Delft
 
The 2-dimensional electron gas as realized in semiconductor heterostructures is an interesting
system to study systems in which the Coulomb interactions energy overpowers the kinetic
energy. A quantum-Wigner crystal might develop, although disorder will play a strong role. In
Si-MOSFETs and in some GaAs heterostructures a critical carrier density is found below which
the system behaves insulating and above which a metallic temperature dependent resistance is
found. The latter is contradicting well-established ideas about localization in 2 dimensions. A
large body of experimental work has been developed and some progess in the theory has been
made, both of which will be presented with an emphasis on results obtained with Si-MOSFETs.