Charge Condensation and Lattice Coupling Drives Stripe Formation in Nickelates

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Correlated materials exhibit complex phenomena like symmetry breaking.
• In La_{2-x}Sr_{x}NiO_{4+δ}, coupled charge and spin stripes emerge at low temperatures.
• Identifying the primary driving force for these stripe orders is challenging due to intertwined degrees of freedom.

Purpose of the Study:

• To investigate the temporal stability and domain memory of charge and spin stripes in La_{2-x}Sr_{x}NiO_{4+δ}.
• To determine the predominant factor governing symmetry breaking in these nickelate materials.

Main Methods:

• Resonant X-ray Photon Correlation Spectroscopy (RXPCS) was employed.
• The study focused on analyzing the dynamics and memory effects of charge and spin stripes.

Main Results:

• Charge stripes exhibit superior temporal stability compared to spin stripes when subjected to temperature changes.
• Charge order displays significant domain memory, persisting even above the ordering temperature up to 250 K.
• Spin stripes are found to be more spatially correlated than charge stripes.

Conclusions:

• Charge stripes are pinned to the lattice, suggesting strong coupling.
• Charge condensation is identified as the predominant driving force for the formation of stripe orders in nickelates.
• These findings clarify the mechanism of symmetry breaking in this class of materials.