Failed excitonic quantum phase transition in Ta2Ni(Se1−xSx)5

@article{Volkov2021FailedEQ,
  title={Failed excitonic quantum phase transition in 
Ta2Ni(Se1−xSx)5},
  author={Pavel A. Volkov and Mai Ye and Himanshu Lohani and Irena Feldman and Amit Kanigel and Girsh Blumberg},
  journal={Physical Review B},
  year={2021}
}
We study the electronic phase diagram of the excitonic insulator candidates Ta2Ni(Se1−xSx)5 [x=0, ... ,1] using polarization resolved Raman spectroscopy. Critical excitonic fluctuations are observed, that diminish with x and ultimately shift to high energies, characteristic of a quantum phase transition. Nonetheless, a symmetry-breaking transition at finite temperatures is detected for all x, exposing a cooperating lattice instability that takes over for large x. Our study reveals a failed… 

Figures from this paper

Lattice dynamics of the Ta2Ni(Se1−xSx)5 excitonic insulator

Lattice dynamics of the Ta2Ni(Se1−xSx)5 excitonic insulator Mai Ye, ∗ Pavel A. Volkov, † Himanshu Lohani, Irena Feldman, Minsung Kim, Amit Kanigel, and Girsh Blumberg 3, ‡ Department of Physics and

Common microscopic origin of the phase transitions in Ta2NiS5 and the excitonic insulator candidate Ta2NiSe5

The structural phase transition in Ta 2 NiSe 5 has been envisioned as driven by the formation of an excitonic insulating phase. However, the role of structural and electronic instabilities on crystal

Second-Order Josephson Effect in Excitonic Insulators.

We show that in electron-hole bilayers with excitonic orders arising from conduction and valence bands formed by atomic orbitals that have different parities, nonzero interlayer tunneling leads to a

Lattice dynamics of the excitonic insulator Ta2Ni(Se1−xSx)5

Recently, we employed electronic polarization-resolved Raman spectroscopy to reveal the strongly correlated excitonic insulator (EI) nature of Ta2NiSe5 [Volkov et al., npj Quant. Mater. 6, 52

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