Optical-phonon-induced frictional drag in coupled two-dimensional electron gases

Abstract

The role of optical phonons in frictional drag between two adjacent but electrically isolated two-dimensional electron gases is investigated. Since the optical phonons in III-V materials have a considerably larger coupling to electrons than acoustic phonons ͑which are the dominant drag mechanism at low T and large separations͒, it might be expected that the optical phonons will contribute a large effect at high temperatures. The two key differences between optical-and acoustic-phonon-mediated drag are ͑i͒ the optical-phonon-mediated interlayer interaction is short-ranged due to the negligible group velocity at the Brillouin zone center, and ͑ii͒ the typical momentum transfer for an optical-phonon-mediated scattering is relatively large. These considerations make optical-phonon-mediated drag difficult to see in single-subband GaAs systems, but it may be possible to see the effect in double-subband GaAs systems or single-subband quantum wells in a material with a lower effective mass and lower optical-phonon energy, such as InSb. ͓S0163-1829͑98͒05219-9͔

Comparative study of screened interlayer interactions in the Coulomb drag effect in bilayer electron systems

“…( 2) should yield values below the experimental measurements for drag resistivity in which all scattering process are included. 11,22,35 Since our calculations already provide a very good agreement with Kellogg et al 8 we can argue that phonon and impurity effects are not very important for these samples. The phonon contribution is identified by the peak in ρ D /T 2 which occurs when the average thermal phonon wave vector becomes comparable to 2k F .…”

Exchange and correlation effects on drag in low density electron bilayers: Coulomb and virtual-optical-phonon-mediated electron–electron interaction

“…This is clearly seen in Ref. [13] where the real-PO-phonon contribution to drag is obtained by a factor of e −28 smaller than the direct Coulomb drag. In stark contrast, scattering by virtual PO-phonons does not imply the energy and momentum conservation and provides an appreciable contribution to drag.…”

Coulomb Drag of Electron-Electron Interactions in GaAs Bilayer with a Non Homogeneous Dielectric Background

“…Whereas the Coulomb mechanism [1,[18][19][20] captures the effect's most qualitative features, such as momentum transfer ℏ may also contributed. Some of suggested the scattering phenemeno involved acoustic [21] and optical [22] phonons, Plasmon effects, and coupled Plasmon phonon modes [23]. Drag effect became an important part for measuring the many body properties, in the index of standard tool box in condensed matter physics of matter, after the turn of the century.…”