1202.2952 (M. Yu. Melnikov et al.)

Influence of e-e scattering on the temperature dependence of the
resistance of a ballistic point-contact in a 2DES    [PDF]

M. Yu. Melnikov, J. P. Kotthaus, V. Pellegrini, L. Sorba, G. Biasiol, V. S. Khrapai

We experimentally investigate the temperature (T) dependence of the
resistance of a ballistic point contact (PC) in a two-dimensional electron
system (2DES). The split-gate PC is realized in a high-quality AlGaAs/GaAs
heterostructure. The PC resistance is found to drop by more than 10% as the T
is raised from 0.5K to 4.2 K. In the absence of magnetic field, the
T-dependence is roughly linear below 2K, and tends to saturate at higher T.
Perpendicular magnetic fields on the order of a few 10mT suppress the
T-dependent contribution dR. This effect is more pronounced at lower
temperatures, causing a crossover to a nearly parabolic T-dependence in
magnetic field. The normalized magnetic field dependencies dR(B) permit an
empiric single parameter scaling in a wide range of PC gate voltages. These
observations give strong evidence for the influence of electron-electron (e-e)
scattering on the resistance of ballistic PCs. Our results are in qualitative
agreement with a recent theory of the e-e scattering based T-dependence of the
conductance of classical ballistic PCs [Phys. Rev. Lett. 101, 216807 (2008)]
and [Phys. Rev. B 81, 125316 (2010)].

View original: http://arxiv.org/abs/1202.2952