Melting of Quasi-Two-Dimensional Charge Stripes in La5/3Sr1/3NiO4

TL;DR

This study investigates the phase transitions and melting behavior of charge stripes in La5/3Sr1/3NiO4 using neutron scattering, revealing a stripe glass intermediate state during the transition from ordered to disordered phases.

Contribution

First neutron experiments on La5/3Sr1/3NiO4 elucidate the sequence of stripe ordering and melting, introducing the concept of a stripe glass state in nickelates.

Findings

Identification of three successive phase transitions with stripe order

Observation of a stripe glass intermediate state during melting

Short-range charge order without spin order in the glass phase

Abstract

Commensurability effects for nickelates have been studied by the first neutron experiments on La5/3Sr1/3NiO4. Upon cooling, this system undergoes three successive phase transitions associated with quasi-two-dimensional (2D) commensurate charge and spin stripe ordering in the NiO$_2$ planes. The two lower temperature phases (denoted as phase II and III) are stripe lattice states with quasi-long-range in-plane charge correlation. When the lattice of 2D charge stripes melts, it goes through an intermediate glass state (phase I) before becoming a disordered liquid state. This glass state shows short-range charge order without spin order, and may be called a "stripe glass" which resembles the hexatic/nematic state in 2D melting.