Observation of spin-charge separation and boundary bound states via the local density of states

TL;DR

This study numerically visualizes spin-charge separation and boundary bound states in a one-dimensional Mott insulator by analyzing the local density of states, revealing dispersing features and boundary effects.

Contribution

It provides a detailed numerical analysis of LDOS in a Hubbard chain, highlighting spin-charge separation and boundary bound states with boundary potential effects.

Findings

Identification of dispersing charge and spin features in LDOS

Visualization of spin-charge separation in a 1D Mott insulator

Detection of boundary bound states within the Mott gap

Abstract

We numerically calculate the local density of states (LDOS) of a one-dimensional Mott insulator with open boundaries, which is modelled microscopically by a (extended) Hubbard chain at half filling. In the Fourier transform of the LDOS we identify several dispersing features corresponding to propagating charge and spin degrees of freedom, thus providing a visualisation of the spin-charge separation in the system. We also consider the effect of an additional boundary potential, which, if sufficiently strong, leads to the formation of a boundary bound state which is clearly visible in the LDOS as a non-dispersing feature inside the Mott gap.