Ultrafast dynamics of vibrational symmetry breaking in a charge-ordered nickelate

Giacomo Coslovich, Alexander F. Kemper, Sascha Behl, Bernhard Huber, Hans A. Bechtel, Takao Sasagawa, Michael C. Martin, Alessandra Lanzara, Robert A. Kaindl

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The ability to probe symmetry-breaking transitions on their natural time scales is one of the key challenges in nonequilibrium physics. Stripe ordering represents an intriguing type of broken symmetry, where complex interactions result in atomic-scale lines of charge and spin density. Although phonon anomalies and periodic distortions attest the importance of electron-phonon coupling in the formation of stripe phases, a direct time-domain view of vibrational symmetry breaking is lacking. We report experiments that track the transient multi-terahertz response of the model stripe compound La1.75Sr0.25NiO4, yielding novel insight into its electronic and structural dynamics following an ultrafast optical quench. We find that although electronic carriers are immediately delocalized, the crystal symmetry remains initially frozen—as witnessed by time-delayed suppression of zone-folded Ni–O bending modes acting as a fingerprint of lattice symmetry. Longitudinal and transverse vibrations react with different speeds, indicating a strong directionality and an important role of polar interactions. The hidden complexity of electronic and structural coupling during stripe melting and formation, captured here within a single terahertz spectrum, opens new paths to understanding symmetry-breaking dynamics in solids.

Original languageEnglish (US)
Article numbere1600735
JournalScience Advances
Issue number11
StatePublished - 2017
Externally publishedYes

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Ultrafast dynamics of vibrational symmetry breaking in a charge-ordered nickelate'. Together they form a unique fingerprint.

Cite this