H. Yayama et al., CARRIER TRANSPORT IN QUASI-ONE-DIMENSIONAL ELECTRON-SYSTEMS OVER LIQUID-HELIUM UNDER STRONG LOCALIZATION CONDITIONS, Low temperature physics, 23(11), 1997, pp. 878-881
The conductivity of carriers in a quasi-one-dimensional electron syste
m over liquid helium is measured in the temperature interval 0.5-1.9 K
in confining electric fields up to 4 kV/cm at a frequency of 1.1 MHz.
Quasi-one-dimensional channels were created by using an optical diffr
action grating covered with a thin helium layer. The carrier conductiv
ity decreases exponentially with temperature T, and the activation ene
rgy is of the order of a few degrees, thus pointing towards localizati
on of electrons in a quasi-one-dimensional electron system. As the thi
ckness of the helium layer covering the grating is increased, a depart
ure from a mono exponential dependence is observed at T<0.8 K, which i
ndicates that quantum effects begin to play an active role in electron
mobility at these temperatures. An analysis of the obtained results l
eads to the assumption that under localization conditions, quasi-one-d
imensional electron systems may contain two branches of the optical mo
de of plasma oscillations, viz., a high-frequency branch associated wi
th electron oscillations in potential wells, and a low-frequency branc
h associated with the oscillations of the electron-dimple complex with
a large effective mass. (C) 1997 American Institute of Physics. [S106
3-777X(97)00311-3].