Failed excitonic quantum phase transition in Ta2Ni (Se1 −xSx)5
Abstract
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 excitonic quantum phase transition, masked by a preemptive structural order.
- Publication:
-
Physical Review B
- Pub Date:
- December 2021
- DOI:
- 10.1103/PhysRevB.104.L241103
- arXiv:
- arXiv:2104.07032
- Bibcode:
- 2021PhRvB.104x1103V
- Keywords:
-
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- Phys. Rev. B 104, L241103 (Letter) (2021)