Probing spin-charge separation in a Tomonaga-Luttinger liquid

TL;DR

This paper reports the experimental observation of spin-charge separation in a one-dimensional electron system, confirming key predictions of the Tomonaga-Luttinger Liquid theory beyond low-energy regimes.

Contribution

The authors experimentally demonstrate spin-charge separation and power-law tunneling suppression in a gated 1D system, extending the validity of TLL effects beyond low energies.

Findings

Confirmed spin-charge separation in a 1D electron system

Observed power-law suppression of tunneling

Demonstrated TLL effects beyond low-energy regimes

Abstract

In a one-dimensional (1D) system of interacting electrons, excitations of spin and charge travel at different speeds, according to the theory of a Tomonaga-Luttinger Liquid (TLL) at low energies. However, the clear observation of this spin-charge separation is an ongoing challenge experimentally. We have fabricated an electrostatically-gated 1D system in which we observe spin-charge separation and also the predicted power-law suppression of tunnelling into the 1D system. The spin-charge separation persists even beyond the low-energy regime where the TLL approximation should hold. TLL effects should therefore also be important in similar, but shorter, electrostatically gated wires, where interaction effects are being studied extensively worldwide.