4.8 Article

Ultrafast melting and recovery of collective order in the excitonic insulator Ta2NiSe5

Journal

NATURE COMMUNICATIONS
Volume 12, Issue 1, Pages -

Publisher

NATURE RESEARCH
DOI: 10.1038/s41467-021-21929-3

Keywords

-

Funding

  1. Engineering and Physical Science Research Council (EPSRC)
  2. Winton Programme for the Physics of Sustainability
  3. Department of Science and Technology (DST), India [SR/WOS-A/PM-33/2018 (G)]
  4. European Research Council (ERC) under the European Union [758826]
  5. Department of Science and Technology, India

Ask authors/readers for more resources

The researchers used ultrafast spectroscopy to study the out-of-equilibrium dynamics of Ta2NiSe5, demonstrating that transient reflectivity in the near-infrared range is connected to low-energy physics. They concluded that electronic correlations play a decisive role in the formation of excitonic order.
The layered chalcogenide Ta2NiSe5 has been proposed to host an excitonic condensate in its ground state, a phase that could offer a unique platform to study and manipulate many-body states at room temperature. However, identifying the dominant microscopic contribution to the observed spontaneous symmetry breaking remains challenging, perpetuating the debate over the ground state properties. Here, using broadband ultrafast spectroscopy we investigate the out-of-equilibrium dynamics of Ta2NiSe5 and demonstrate that the transient reflectivity in the near-infrared range is connected to the system's low-energy physics. We track the status of the ordered phase using this optical signature, establishing that high-fluence photoexcitations can suppress this order. From the sub-50 fs quenching timescale and the behaviour of the photoinduced coherent phonon modes, we conclude that electronic correlations provide a decisive contribution to the excitonic order formation. Our results pave the way towards the ultrafast control of an exciton condensate at room temperature. The dominant mechanism of the excitonic insulator transition in Ta2NiSe5 and the nature of its high-temperature phase are debated. The authors report transient reflectivity measurements indicating a significant electronic contribution to the transition and a gapped state of preformed excitons at high temperatures.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.8
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available