Nonlinear spectra of spinons and holons in short GaAs quantum wires

TL;DR

This study experimentally investigates the nonlinear spectral features of short GaAs quantum wires, confirming key predictions of recent nonlinear theories about spinon and holon excitations in one-dimensional electronic systems.

Contribution

The paper provides the first experimental evidence of nonlinear spinon and holon bands in short GaAs quantum wires, validating recent theoretical models.

Findings

Evidence of an inverted spinon shadow band in the particle sector

Observation of a holon band with reduced effective mass at high energies

Confirmation of nonlinear spectral predictions in 1D quantum wires

Abstract

One-dimensional electronic fluids are peculiar conducting systems, where the fundamental role of interactions leads to exotic, emergent phenomena, such as spin-charge (spinon-holon) separation. The distinct low-energy properties of these 1D metals are successfully described within the theory of linear Luttinger liquids, but the challenging task of describing their high-energy nonlinear properties has long remained elusive. Recently, novel theoretical approaches accounting for nonlinearity have been developed, yet the rich phenomenology that they predict remains barely explored experimentally. Here, we probe the nonlinear spectral characteristics of short GaAs quantum wires by tunnelling spectroscopy, using an advanced device consisting of 6000 wires. We find evidence for the existence of an inverted (spinon) shadow band in the main region of the particle sector, one of the central predictions of the new nonlinear theories. A (holon) band with reduced effective mass is clearly visible in the particle sector at high energies.