Probing Tomonaga-Luttinger Liquid behaviour in GaAs quantum wires with a two-dimensional electron gas
Nanoscience Technology Center and Department of Physics, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826 USA.
Mercredi 15/04/2009, 11:15
SPEC Salle Itzykson, Bât.774, Orme des Merisiers
Coulomb interactions have been predicted to have a profound effect on the
behaviour of electrons in one dimension as predicted for a spin-charge separation of a
Tomonaga-Luttinger Liquid (TLL), the simplest analytic model of an interacting 1D
system. Verification of a TLL is an important goal in experimental solid-state physics,
with relevance to quantum devices and the theory of high-Tc superconductors.
Determining the extent of its applicability would also provide a major test of more
general methods of modelling interaction effects. In this talk, I will present the
experimental results from momentum-conserved tunnelling between an array of GaAs
quantum wires (1D) and adjacent two-dimensional electron gas (2D), in which we
observed spin-charge separation and a power-law suppression of tunnelling into the
wires . The use of an array of wires averages out impurity effects and allows the
lowest 1D subband to be probed with precise control of electron density . We
observed spin-charge separation in the dispersion relation of the 1D wires by
measuring tunnelling conductance whilst varying the in-plane magnetic field and the
dc-bias simultaneously. We find that the separation persists beyond the regime where
the TLL approximation should hold. Furthermore, the measured 1D-2D tunnelling
current is suppressed at zero dc-bias in the presence of a magnetic field, confirming
that interactions are important in these quantum wires. This suppression has been
measured as a function of temperature and source-drain voltage and both have similar
power-law dependences. We compare the interaction parameters deduced from each
of these measurements.
 Y. Jompol, C. F. B. Ford, J. P. Griffiths, I. Farer, D. Anderson, D. A. Ritchie,
T.W. Silk, and A.J. Schofield, Spin-charge separation in a Tomonaga-Luttinger
liquid probed by tunnelling into a two-dimensional electron gas (under peer review
for a publication in Science).
 Y. Jompol, C. F. B. Ford, I. Farer, D. Anderson, D. A. Ritchie, T. W. Silk, and
A.J. Schofield, Probing e–e interactions in a periodic array of GaAs quantum wires,
Physica E 40, 1220 (2008).