Charge and Spin Dynamics of an Ordered Stripe Phase in La_(1 2/3)Sr_(1/3)NiO_4 by Raman Spectroscopy

TL;DR

This study uses Raman spectroscopy to investigate charge and spin dynamics in the stripe phase of La_(1 2/3)Sr_(1/3)NiO_4, revealing superlattice formation, pseudo-gap opening, and persistent stripe fluctuations.

Contribution

It provides new insights into the interplay between charge and spin orderings and the nature of stripe fluctuations in a doped Mott-Hubbard system.

Findings

Superlattice formation observed below charge-ordering transition

Pseudo-gap opens in electron-hole excitation spectra

Persistent stripe fluctuations above the transition

Abstract

For La_(1 2/3)Sr_(1/3)NiO_4 -- a commensurately doped Mott-Hubbard system -- charge- and spin-ordering in a stripe phase has been investigated by phononic and magnetic Raman scattering. Formation of a superlattice and an opening of a pseudo-gap in the electron-hole excitation spectra as well as two types of double-spin excitations -- within the antiferromagnetic domain and across the domain wall -- are observed below the charge-ordering transition. The temperature dependence suggests that the spin ordering is driven by charge ordering and that fluctuating stripes persist above the ordering transition.