Probing e–e interactions in a periodic array of GaAs quantum wires

Abstract

We present the results of non-linear tunnelling spectroscopy between an array of independent quantum wires and an adjacent two-dimensional electron gas (2DEG) in a double-quantum-well structure. The two layers are separately contacted using a surface-gate scheme, and the wires are all very regular, with dimensions chosen carefully so that there is minimal modulation of the 2DEG by the gates defining the wires. We have mapped the dispersion spectrum of the 1D wires down to the depletion of the last 1D subband by measuring the conductance G as a function of the in-plane magnetic field B, the interlayer bias V dc and the wire gate voltage. There is a strong suppression of tunnelling at zero bias, with temperature and dc-bias dependences consistent with power laws, as expected for a Tomonaga-Luttinger Liquid caused by electron-electron interactions in the wires. In addition, the current peaks fit the free-electron model quite well, but with just one 1D subband there is extra structure that may indicate interactions. adjacent low-disorder 2D layer depends on the overlap between the spectral functions of the two systems, which is varied by using an in-plane magnetic field B perpendicular to the wires to offset the two in k-space; a bias V dc between the layers is used to investigate the energy dependence. In a non-interacting system, peaks in the conductance G follow the 1D and 2D subbands. In contrast, for a TLL, there should be two features, for spin and charge, instead of one for a non-interacting 1D subband. [6,7] We have previously used ion-beam lithography to make separate contact to two such layers of electrons, for investigating arrays of 1D wires [8] and antidots [9], but here we adopt a simpler technique that uses just

Quantum interference and spin-charge separation in a disordered Luttinger liquid

“…In recent years, progress in nanofabrication technologies has made it possible to manufacture a variety of single-and few-channel quantum wires connected to the electric leads and to perform systematic transport measurements on the very narrow wires. The latter include single-wall carbon nanotubes 8,9,10,11,12,13,14 , semiconductor-based 15,16,17,18 and metallic 19 quantum wires, polymer nanofibers 20 , as well as quantum Hall edge states. 21,22 The LL nature of these strongly correlated quantum wires has been supported by a wealth of experimental findings.…”