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 Tc=200 K in the strongly spin-orbit coupled correlated metal Cd2Re2O7. We establish that the structural distortion at Tc 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 Tc. 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.
| Original language | English |
|---|---|
| Article number | 047601 |
| Journal | Physical Review Letters |
| Volume | 120 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 24 2018 |
Funding
This work was supported by the U.S. Department of Energy under Grant No. DE-SC0010533. D.\u2009H. also acknowledges funding from the David and Lucile Packard Foundation and support for instrumentation from the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (PHY-1125565) with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250. J.-Q.\u2009Y. and D.\u2009G.\u2009M. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. Z.\u2009Y.\u2009Z. acknowledges the Center for Emergent Materials, an NSF Materials Research Science and Engineering Center under Grant No. DMR-1420451. The work of D.\u2009M.\u2009K. and A.\u2009J.\u2009M. on this project was supported by the Basic Energy Sciences Program of the U.S. Department of Energy under Grant No. SC-0012375, and D.\u2009M.\u2009K. also acknowledges DFG KE 2115/1-1.