H. Rubel et al., THE FRICTIONAL DRAG BETWEEN COUPLED 2-DIMENSIONAL ELECTRONIC SYSTEMS IN MAGNETIC-FIELDS, Physica. B, Condensed matter, 251, 1998, pp. 859-863
The coupling between systems of two spatially separated two-dimensiona
l (2D) electron gases and between systems of a separated 2D electron g
as and a 2D hole gas is studied as a function of magnetic field B. The
coupled electron gases with a barrier of 30 nm showed a transition fr
om a phonon-dominated interaction at B = 0 to a Coulomb dominated one
at quantising fields. For larger barriers (190 nm), phonons have been
found to be the dominant coupling mechanism both at zero and finite fi
elds. However, for all barriers investigated, we could observe a suppr
ession of the coupling at half-filled Landau-levels probably due to no
vel screening effects. In the case of the coupled electron-hole gas sa
mples with large barriers (>190 nm) we have investigated, the enhanced
screening effects could not be observed possibly due to the less pron
ounced quantisation of the hole gas. (C) 1998 Elsevier Science B.V. Al
l rights reserved.