Diffusion and ballistic contributions of the interaction correction to   the conductivity of a two-dimensional electron gas
  The results of an experimental study of interaction quantum correction to the conductivity of two-dimensional electron gas in A$_3$B$_5$ semiconductor quantum well heterostructures are presented for a wide range of $T\tau$-parameter ($T\tau\simeq 0.03-0.8$), where $\tau$ is the transport relaxation time. A comprehensive analysis of the magnetic field and temperature dependences of the resistivity and the conductivity tensor components allows us to separate the ballistic and diffusion parts of the correction. It is shown that the ballistic part renormalizes in the main the electron mobility, whereas the diffusion part contributes to the diagonal and does not to the off-diagonal component of the conductivity tensor. We have experimentally found the values of the Fermi-liquid parameters describing the electron-electron contribution to the transport coefficients, which are found in a good agreement with the theoretical results. 
G.M.Minkov, A.A.Sherstobitov, A.V.Germanenko, O.E.Rut, V.A.Larionova,   A.K.Bakarov, B.N.Zvonkov