English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The complex Fermi surfaces of transition-metal dichalcogenides (TMDCs)challenge the standard Peierls-instability-driven charge-density-wave (CDW)formation. Recently, evidence has been accumulating of a prominent role ofionic thermal fluctuations, which frozen out below $T_{CDW}$ inducing aperiodic lattice distortion (PLD). We focus on $2H$-NbSe$_2$, displaying aquasi-commensurate CDW below $T_{CDW}$ $\approx$33 K, and use time-resolvedoptical spectroscopy (TR-OS) to detect and disentangle the electronic andlattice degrees of freedom. We reveal a fingerprint of the ordered phase ath$\nu$ $\sim$1 eV: at $T_{CDW}$, a divergent relaxation timescale and asign-change of the differential reflectivity indicate that CDW gap opening andPLD formation occur at the same temperature. However, we show that theseeffects can be decoupled under moderate photoexcitation, forming a long-livedstate in which the electronic order is destroyed, but the lattice distortion isnot. Our results and computations suggest an unconventional CDW mechanims in$2H$-NbSe$_2$, highlighting the dominant role of the lattice in driving theordered-phase formation.

Lattice contribution to the unconventional charge density wave transition in $2H$-NbSe$_2$: a non-equilibrium optical approach