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.