Nuclear magnetism and electron order in interacting one-dimensional conductors

TL;DR

This paper demonstrates that weak hyperfine interactions in one-dimensional conductors like carbon nanotubes and GaAs wires can induce a coupled nuclear-electronic ordered phase, revealing strong Luttinger liquid effects and reducing conductance.

Contribution

It shows that nuclear spin order can be triggered by electron interactions in 1D systems, leading to a unique coupled phase observable in experiments.

Findings

Nuclear spins form a helimagnet tightly bound to electronic density waves.

The ordered phase persists up to millikelvin temperatures.

Electric conductance is reduced by a universal factor of 2.

Abstract

The interaction between localized magnetic moments and the electrons of a one-dimensional conductor can lead to an ordered phase in which the magnetic moments and the electrons are tightly bound to each other. We show here that this occurs when a lattice of nuclear spins is embedded in a Luttinger liquid. Experimentally available examples of such a system are single wall carbon nanotubes grown entirely from 13C and GaAs-based quantum wires. In these systems the hyperfine interaction between the nuclear spin and the conduction electron spin is very weak, yet it triggers a strong feedback reaction that results in an ordered phase consisting of a nuclear helimagnet that is inseparably bound to an electronic density wave combining charge and spin degrees of freedom. This effect can be interpreted as a strong renormalization of the nuclear Overhauser field and is a unique signature of Luttinger liquid physics. Through the feedback the order persists up into the millikelvin range. A particular signature is the reduction of the electric conductance by the universal factor 2.