Speaker
Description
A charge density wave (CDW) is a phase of matter characterized by a periodic modulation of valence electron density coupled to a lattice distortion. In 1979, Alan Heeger predicted that the CDW transition should be accompanied by a divergence in the dynamic charge susceptibility, but this effect has never been observed experimentally. In this talk I will present momentum-resolved inelastic electron scattering (EELS) measurements of the charge susceptibility in the canonical CDW material ErTe3 with meV energy resolution. The valence band electronic excitations exhibit relaxational dynamics that are described well by a diffusion model, with the diffusivity peaking just below the critical temperature. Additionally, I will show, for the first time, a divergence in the real part of in the static limit ( )—a long-predicted hallmark of CDWs. Unexpectedly, this divergence occurs as with only a weak thermodynamic signature at the transition temperature. Our study necessitates a reexamination of the traditional description of CDW formation in quantum materials.
*D. Chaudhuri, et al., arXiv:2411.14746 (to appear in PNAS)
| Topical Area | Hard matter: quantum, electronic, semiconducting materials |
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