Related Experiment Video
Updated: Feb 14, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Evidence of an Improper Displacive Phase Transition in Cd_{2}Re_{2}O_{7} via Time-Resolved Coherent Phonon
J W Harter1,2, D M Kennes3, H Chu2,4
1Department of Physics, California Institute of Technology, Pasadena, California 91125, USA.
Abstract:
We have used a combination of ultrafast coherent phonon spectroscopy, ultrafast thermometry, and time-dependent Landau theory to study the inversion symmetry breaking phase transition at T_{c}=200 K in the strongly spin-orbit coupled correlated metal Cd_{2}Re_{2}O_{7}. We establish that the structural distortion at T_{c} is a secondary effect through the absence of any softening of its associated phonon mode, which supports a purely electronically driven mechanism. However, the phonon lifetime exhibits an anomalously strong temperature dependence that decreases linearly to zero near T_{c}. We show that this behavior naturally explains the spurious appearance of phonon softening in previous Raman spectroscopy experiments and should be a prevalent feature of correlated electron systems with linearly coupled order parameters.
Related Concept Videos
SN2 Reaction: Transition State
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
Phase Transitions
Phase Transitions: Sublimation and Deposition
Phase Transitions: Melting and Freezing
Phase Transitions: Vaporization and Condensation
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H

