EXPERIMENTS ON ORDERING IN CLASSICAL AND QUANTUM 2D ELECTRON-SYSTEMS

Experimental studies of the magnetically induced Wigner solidification for electrons at high quality GaAs/Ga(Al)As heterojunctions in the extreme quantum limit and of the classical electron solidification for electrons on the helium surface are described. The use of a radiofrequency broadband spectroscopy technique to observe the low lying electronic collective excitations has led to the observation of the phase diagram of the quantum phase, the shear modulus and the specific heat of the classical phase. © 1990.