Session O17 - Heterostructures: General.
MIXED session, Thursday afternoon, March 20
Room 2215, Conv. Center
The low temperature energy and momentum relaxation rates of 2D electron gas placed near the free or clamped surface of a semi--infinit sample are calculated. To describe the electron--acoustic phonon interaction with allowance of the surface effect the method of elasticity theory Green functions was used. This method allows to take into account the reflection of acoustic waves from the surface and related mutual conversion of LA and TA waves. It is shown that the strength of the deformation potential scattering at low temperatures substantially depends on the mechanical conditions at the surface: relaxation rates are suppressed for the free surface while for the rigid one the rates are enhanced. The dependence of the conductivity on the distance between the 2D layer and the surface is discussed. The effect is most pronounced in the range of temperatures 2 s_l p_F < T < (2 \hbar s_l)/d, where p_F is the Fermi momentum, s_l is the velocity of LA waves, d is the width of the quantum well.