PT Journal
AU Verevkin, AA
   Ptitsina, NG
   Chulcova, GM
   Gol'Tsman, GN
   Gershenzon, EM
   Yngvesson, KS
TI Determination of the limiting mobility of a two-dimensional electron gas in Al[sub:x]Ga[sub:1-x]As/GaAs heterostructures and direct measurement of the energy relaxation time
SO Phys. Rev. B Condens. Matter.
JI Phys. Rev. B Condens. Matter.
PY 1996
BP R7592-R7595
VL 53
IS 12
DI 10.1103/physrevb.53.r7592
DE 2DEG; AlGaAs/GaAs heterostructures
AB We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility.
ER