Transport properties for a dilute solution of3He in two-dimensional liquid4He

Abstract

The temperature variations of the diffusion coefficientD(T), thermal diffusion ratio kT(T) and thermal conductivity κ(T) in a dilute solution of3He atom in two-dimensional liquid helium are evaluated explicitly by solving the kinetic equations via phonon-phonon, phonon-roton, roton-roton, impurityelementary excitation and impurity-impurity scatterings. In the low-temperature region, the main contributions toD(T) and κ(T) come from the interactions between phonons and impurities, while in the high-temperature region the interactions between impurities and whole elementary excitations contribute more strongly toD(T) and κ(T) than those of only elementary excitations. For a dilute solution, the thermal diffusion ratio kT(T), neglecting the internal mass counterflow, is much smaller than the effective thermal diffusion ratio kT*(T), which is a function of thermostatic properties. The effective thermal conductivity κeff is much larger than the thermal conductivity and has different temperature dependence from the thermal conductivity. The behaviors of the two-dimensional diffusion coefficient and thermal conductivity are much like the bulk case, where they exhibit exponential decay with increasing temperature, although they are much smaller than those of the bulk case.