- Physical Review Journals
All JournalsPhysics Magazine

Physical Review B

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Letter
  • Open Access

Collective modes and Raman response in Ta2NiSe5

Banhi Chatterjee1, Jernej Mravlje1,2, and Denis Golež1,2

PDF

Phys. Rev. B 111, L121106 – Published 18 March, 2025

DOI: https://doi.org/10.1103/PhysRevB.111.L121106

Abstract

We explore the collective response in an excitonic insulator phase in Ta2NiSe5 using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within a time-dependent Hartree-Fock approach. Contrary to the standard expectations, the amplitude mode frequency does not coincide with the single-particle gap but has a higher frequency. We find a phase mode that is massive because the excitonic condensation breaks a discrete symmetry only and that becomes heavier as the electron-lattice coupling is increased. These features are expected to apply to generic realistic excitonic insulators. We discuss scenarios under which the phase mode does not appear as a sharp in-gap resonance.

View figure in article

Physics Subject Headings (PhySH)

Article Text

Supplemental Material

References (68)

  1. J. D. Cloizeaux, Exciton instability and crystallographic anomalies in semiconductors, J. Phys. Chem. Solids 26, 259 (1965).
  2. D. Jérome, T. Rice, and W. Kohn, Excitonic insulator, Phys. Rev. 158, 462 (1967).
  3. J. Kuneš, Excitonic condensation in systems of strongly correlated electrons, J. Phys.: Condens. Matter 27, 333201 (2015).
  4. J. Eisenstein, Exciton condensation in bilayer quantum Hall systems, Annu. Rev. Condens. Matter Phys. 5, 159 (2014).
  5. J. I. A. Li, T. Taniguchi, K. Watanabe, J. Hone, and C. R. Dean, Excitonic superfluid phase in double bilayer graphene, Nat. Phys. 13, 751 (2017).
  6. X. Liu, K. Watanabe, T. Taniguchi, B. I. Halperin, and P. Kim, Quantum Hall drag of exciton condensate in graphene, Nat. Phys. 13, 746 (2017).
  7. Z. Wang, D. A. Rhodes, K. Watanabe, T. Taniguchi, J. C. Hone, J. Shan, and K. F. Mak, Evidence of high-temperature exciton condensation in two-dimensional atomic double layers, Nature (London) 574, 76 (2019).
  8. S. Gupta, A. Kutana, and B. I. Yakobson, Heterobilayers of 2D materials as a platform for excitonic superfluidity, Nat. Commun. 11, 2989 (2020).
  9. F. Nilsson, M. Kuisma, S. Pakdel, and K. S. Thygesen, Excitonic insulators and superfluidity in two-dimensional bilayers without external fields, J. Phys. Chem. Lett. 14, 2277 (2023).
  10. G. Mazza, M. Rösner, L. Windgätter, S. Latini, H. Hübener, A. J. Millis, A. Rubio, and A. Georges, Nature of symmetry breaking at the excitonic insulator transition: Ta2NiSe5, Phys. Rev. Lett. 124, 197601 (2020).
  11. H. Cercellier, C. Monney, F. Clerc, C. Battaglia, L. Despont, M. G. Garnier, H. Beck, P. Aebi, L. Patthey, H. Berger, and L. Forró, Evidence for an excitonic insulator phase in 1T−TiSe2, Phys. Rev. Lett. 99, 146403 (2007).
  12. C. Monney, E. F. Schwier, M. G. Garnier, N. Mariotti, C. Didiot, H. Beck, P. Aebi, H. Cercellier, J. Marcus, C. Battaglia, H. Berger, and A. N. Titov, Temperature-dependent photoemission on 1T-TiSe2: Interpretation within the exciton condensate phase model, Phys. Rev. B 81, 155104 (2010).
  13. A. Kogar, M. S. Rak, S. Vig, A. A. Husain, F. Flicker, Y. I. Joe, L. Venema, G. J. MacDougall, T. C. Chiang, E. Fradkin et al., Signatures of exciton condensation in a transition metal dichalcogenide, Science 358, 1314 (2017).
  14. Z. Li, M. Nadeem, Z. Yue, D. Cortie, M. Fuhrer, and X. Wang, Possible excitonic insulating phase in quantum-confined Sb nanoflakes, Nano Lett. 19, 4960 (2019).
  15. P. Zhang, Y. Dong, D. Yan, B. Jiang, T. Yang, J. Li, Z. Guo, Y. Huang, Q. Li, Y. Li et al., Spontaneous gap opening and potential excitonic states in an ideal Dirac semimetal Ta2Pd3Te5, Phys. Rev. X 14, 011047 (2024).
  16. M. S. Hossain, T. A. Cochran, Y.-X. Jiang, S. Zhang, H. Wu, X. Liu, X. Zheng, B. Kim, G. Cheng, Q. Zhang et al., Discovery of a topological exciton insulator with tunable momentum order, arXiv:2312.15862.
  17. J. Huang, B. Jiang, J. Yao, D. Yan, X. Lei, J. Gao, Z. Guo, F. Jin, Y. Li, Z. Yuan et al., Evidence for an excitonic insulator state in Ta2Pd3Te5, Phys. Rev. X 14, 011046 (2024).
  18. J. Yao, H. Sheng, R. Zhang, Q. Wu, H. Weng, X. Dai, Z. Fang, and Z. Wang, Excitonic instability in Ta2Pd3Te5, Chin. Phys. Lett. 41, 097101 (2024).
  19. Y. Wakisaka, T. Sudayama, K. Takubo, T. Mizokawa, M. Arita, H. Namatame, M. Taniguchi, N. Katayama, M. Nohara, and H. Takagi, Excitonic insulator state in Ta2NiSe5 probed by photoemission spectroscopy, Phys. Rev. Lett. 103, 026402 (2009).
  20. F. Di Salvo, C. Chen, R. Fleming, J. Waszczak, R. Dunn, S. Sunshine, and J. A. Ibers, Physical and structural properties of the new layered compounds Ta2NiS5 and Ta2NiSe5, J. Less-Common Met. 116, 51 (1986).
  21. Y. Lu, H. Kono, T. Larkin, A. Rost, T. Takayama, A. Boris, B. Keimer, and H. Takagi, Zero-gap semiconductor to excitonic insulator transition in Ta2NiSe5, Nat. Commun. 8, 14408 (2017).
  22. T. I. Larkin, A. N. Yaresko, D. Pröpper, K. A. Kikoin, Y. F. Lu, T. Takayama, Y.-L. Mathis, A. Rost, H. Takagi, B. Keimer et al., Giant exciton Fano resonance in quasi-one-dimensional Ta2NiSe5, Phys. Rev. B 95, 195144 (2017).
  23. T. I. Larkin, R. D. Dawson, M. Höppner, T. Takayama, M. Isobe, Y.-L. Mathis, H. Takagi, B. Keimer, and A. V. Boris, Infrared phonon spectra of quasi-one-dimensional Ta2NiSe5 and Ta2NiS5, Phys. Rev. B 98, 125113 (2018).
  24. S. A. Sunshine and J. A. Ibers, Structure and physical properties of the new layered ternary chalcogenides tantalum nickel sulfide (Ta2NiS5) and tantalum nickel selenide (Ta2NiSe5), Inorg. Chem. 24, 3611 (1985).
  25. Y. Wakisaka, T. Sudayama, K. Takubo, T. Mizokawa, N. Saini, M. Arita, H. Namatame, M. Taniguchi, N. Katayama, M. Nohara et al., Photoemission spectroscopy of Ta2NiSe5, J. Supercond. Novel Magn. 25, 1231 (2012).
  26. K. Seki, Y. Wakisaka, T. Kaneko, T. Toriyama, T. Konishi, T. Sudayama, N. L. Saini, M. Arita, H. Namatame, M. Taniguchi et al., Excitonic Bose-Einstein condensation in Ta2NiSe5 above room temperature, Phys. Rev. B 90, 155116 (2014).
  27. S. Mor, M. Herzog, D. Golež, P. Werner, M. Eckstein, N. Katayama, M. Nohara, H. Takagi, T. Mizokawa, C. Monney, and J. Stähler, Ultrafast electronic band gap control in an excitonic insulator, Phys. Rev. Lett. 119, 086401 (2017).
  28. S. Mor, M. Herzog, J. Noack, N. Katayama, M. Nohara, H. Takagi, A. Trunschke, T. Mizokawa, C. Monney, and J. Stähler, Inhibition of the photoinduced structural phase transition in the excitonic insulator Ta2NiSe5, Phys. Rev. B 97, 115154 (2018).
  29. K. Okazaki, Y. Ogawa, T. Suzuki, T. Yamamoto, T. Someya, S. Michimae, M. Watanabe, Y. Lu, M. Nohara, H. Takagi, N. Katayama, H. Sawa, M. Fujisawa, T. Kanai, N. Ishii, J. Itatani, T. Mizokawa, and S. Shin, Photo-induced semimetallic states realised in electron–hole coupled insulators, Nat. Commun. 9, 4322 (2018).
  30. H. M. Bretscher, P. Andrich, P. Telang, A. Singh, L. Harnagea, A. K. Sood, and A. Rao, Ultrafast melting and recovery of collective order in the excitonic insulator Ta2NiSe5, Nat. Commun. 12, 1699 (2021).
  31. H. M. Bretscher, P. Andrich, Y. Murakami, D. Golež, B. Remez, P. Telang, A. Singh, L. Harnagea, N. R. Cooper, A. J. Millis, P. Werner, A. K. Sood, and A. Rao, Imaging the coherent propagation of collective modes in the excitonic insulator Ta2NiSe5 at room temperature, Sci. Adv. 7, eabd6147 (2021).
  32. T. Saha, D. Golež, G. De Ninno, J. Mravlje, Y. Murakami, B. Ressel, M. Stupar, and P. c. v. R. Ribič, Photoinduced phase transition and associated timescales in the excitonic insulator Ta2NiSe5, Phys. Rev. B 103, 144304 (2021).
  33. L. Geng, X. Liu, J. Zhang, D. Golež, and L.-Y. Peng, Anomalous photo-induced band renormalization in correlated materials: Case study of Ta2NiSe5, arXiv:2401.16988.
  34. A. Nakano, T. Nagai, N. Katayama, H. Sawa, H. Taniguchi, and I. Terasaki, Exciton transport in the electron–hole system Ta2NiSe5, J. Phys. Soc. Jpn. 88, 113706 (2019).
  35. T. Kaneko, T. Toriyama, T. Konishi, and Y. Ohta, Electronic structure of Ta2NiSe5 as a candidate for excitonic insulators, J. Phys.: Conf. Ser. 400, 032035 (2012).
  36. T. Kaneko, T. Toriyama, T. Konishi, and Y. Ohta, Orthorhombic-to-monoclinic phase transition of Ta2NiSe5 induced by the Bose-Einstein condensation of excitons, Phys. Rev. B 87, 035121 (2013).
  37. A. Subedi, Orthorhombic-to-monoclinic transition in Ta2NiSe5 due to a zone-center optical phonon instability, Phys. Rev. Mater. 4, 083601 (2020).
  38. M. D. Watson, I. Marković, E. A. Morales, P. Le Fèvre, M. Merz, A. A. Haghighirad, and P. D. C. King, Band hybridization at the semimetal-semiconductor transition of Ta2NiSe5 enabled by mirror-symmetry breaking, Phys. Rev. Res. 2, 013236 (2020).
  39. L. Windgätter, M. Rösner, G. Mazza, H. Hübener, A. Georges, A. J. Millis, S. Latini, and A. Rubio, Common microscopic origin of the phase transitions in Ta2NiS5 and the excitonic insulator candidate Ta2NiSe5, npj Comput. Mater. 7, 210 (2021).
  40. E. Baldini, A. Zong, D. Choi, C. Lee, M. H. Michael, L. Windgaetter, I. I. Mazin, S. Latini, D. Azoury, B. Lv et al., The spontaneous symmetry breaking in Ta2NiSe5 is structural in nature, Proc. Natl. Acad. Sci. USA 120, e2221688120 (2023).
  41. M. Ye, P. A. Volkov, H. Lohani, I. Feldman, M. Kim, A. Kanigel, and G. Blumberg, Lattice dynamics of the excitonic insulator Ta2Ni(Se1−xSx)5, Phys. Rev. B 104, 045102 (2021).
  42. D. Golež, S. K. Y. Dufresne, M.-J. Kim, F. Boschini, H. Chu, Y. Murakami, G. Levy, A. K. Mills, S. Zhdanovich, M. Isobe, H. Takagi, S. Kaiser, P. Werner, D. J. Jones, A. Georges, A. Damascelli, and A. J. Millis, Unveiling the underlying interactions in Ta2NiSe5 from photoinduced lifetime change, Phys. Rev. B 106, L121106 (2022).
  43. M.-J. Kim, A. Schulz, T. Takayama, M. Isobe, H. Takagi, and S. Kaiser, Phononic soft mode behavior and a strong electronic background across the structural phase transition in the excitonic insulator Ta2NiSe5, Phys. Rev. Res. 2, 042039(R) (2020).
  44. K. Kim, H. Kim, J. Kim, C. Kwon, J. S. Kim, and B. Kim, Direct observation of excitonic instability in Ta2NiSe5, Nat. Commun. 12, 1969 (2021).
  45. P. A. Volkov, M. Ye, H. Lohani, I. Feldman, A. Kanigel, and G. Blumberg, Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator, npj Quantum Mater. 6, 52 (2021).
  46. P. A. Volkov, M. Ye, H. Lohani, I. Feldman, A. Kanigel, and G. Blumberg, Failed excitonic quantum phase transition in Ta2Ni(Se1−xSx)5, Phys. Rev. B 104, L241103 (2021).
  47. J. Yan, R. Xiao, X. Luo, H. Lv, R. Zhang, Y. Sun, P. Tong, W. Lu, W. Song, X. Zhu et al., Strong electron–phonon coupling in the excitonic insulator Ta2NiSe5, Inorg. Chem. 58, 9036 (2019).
  48. K. Katsumi, A. Alekhin, S.-M. Souliou, M. Merz, A.-A. Haghighirad, M. Le Tacon, S. Houver, M. Cazayous, A. Sacuto, and Y. Gallais, Disentangling lattice and electronic instabilities in the excitonic insulator candidate Ta2NiSe5 by nonequilibrium spectroscopy, Phys. Rev. Lett. 130, 106904 (2023).
  49. T. Tang, H. Wang, S. Duan, Y. Yang, C. Huang, Y. Guo, D. Qian, and W. Zhang, Non-coulomb strong electron-hole binding in Ta2NiSe5 revealed by time-and angle-resolved photoemission spectroscopy, Phys. Rev. B 101, 235148 (2020).
  50. D. Werdehausen, T. Takayama, M. Höppner, G. Albrecht, A. W. Rost, Y. Lu, D. Manske, H. Takagi, and S. Kaiser, Coherent order parameter oscillations in the ground state of the excitonic insulator Ta2NiSe5, Sci. Adv. 4, eaap8652 (2018).
  51. S. R. U. Haque, M. H. Michael, J. Zhu, Y. Zhang, L. Windgätter, S. Latini, J. P. Wakefield, G.-F. Zhang, J. Zhang, A. Rubio, J. G. Checkelsky, E. Demler, and R. D. Averitt, Terahertz parametric amplification as a reporter of exciton condensate dynamics, Nat. Mater. 23, 796 (2024).
  52. See Supplemental Material at http://link.aps.org/supplemental/10.1103/PhysRevB.111.L121106 for details of the model and the method used to evaluate the Raman spectrum and corrections beyond the Hartree-Fock, which also includes Refs. [64, 65, 66, 67, 68].
  53. K. Sugimoto, T. Kaneko, and Y. Ohta, Microscopic quantum interference in excitonic condensation of Ta2NiSe5, Phys. Rev. B 93, 041105(R) (2016).
  54. Y. Murakami, D. Golež, T. Kaneko, A. Koga, A. J. Millis, and P. Werner, Collective modes in excitonic insulators: Effects of electron-phonon coupling and signatures in the optical response, Phys. Rev. B 101, 195118 (2020).
  55. Y. Murakami, D. Golež, M. Eckstein, and P. Werner, Photoinduced enhancement of excitonic order, Phys. Rev. Lett. 119, 247601 (2017).
  56. J. R. Schrieffer, Theory of Superconductivity (CRC Press, Boca Raton, FL, 2018).
  57. M. H. Michael, S. R. U. Haque, L. Windgaetter, S. Latini, Y. Zhang, A. Rubio, R. D. Averitt, and E. Demler, Photonic time-crystalline behaviour mediated by phonon squeezing in Ta2NiSe5, Nat. Commun. 15, 3638 (2024).
  58. D. Golež, Z. Sun, Y. Murakami, A. Georges, and A. J. Millis, Nonlinear spectroscopy of collective modes in an excitonic insulator, Phys. Rev. Lett. 125, 257601 (2020).
  59. T. Tanabe, T. Kaneko, and Y. Ohta, Third-harmonic generation in excitonic insulators, Phys. Rev. B 104, 245103 (2021).
  60. R. Matsunaga, Y. I. Hamada, K. Makise, Y. Uzawa, H. Terai, Z. Wang, and R. Shimano, Higgs amplitude mode in the BCS superconductors Nb1−xTixN induced by terahertz pulse excitation, Phys. Rev. Lett. 111, 057002 (2013).
  61. R. Matsunaga, N. Tsuji, H. Fujita, A. Sugioka, K. Makise, Y. Uzawa, H. Terai, Z. Wang, H. Aoki, and R. Shimano, Light-induced collective pseudospin precession resonating with Higgs mode in a superconductor, Science 345, 1145 (2014).
  62. N. Tsuji and H. Aoki, Theory of Anderson pseudospin resonance with Higgs mode in superconductors, Phys. Rev. B 92, 064508 (2015).
  63. T. Blommel, J. Kaye, Y. Murakami, E. Gull, and D. Golež, Chirped amplitude mode in photo-excited superconductors, arXiv:2403.01589.
  64. G. Onida, L. Reining, and A. Rubio, Electronic excitations: Density-functional versus many-body Green's-function approaches, Rev. Mod. Phys. 74, 601 (2002).
  65. T. Kaneko, Z. Sun, Y. Murakami, D. Golež, and A. J. Millis, Bulk photovoltaic effect driven by collective excitations in a correlated insulator, Phys. Rev. Lett. 127, 127402 (2021).
  66. C. Shao, T. Tohyama, H.-G. Luo, and H. Lu, Numerical method to compute optical conductivity based on pump-probe simulations, Phys. Rev. B 93, 195144 (2016).
  67. M. Schüler, D. Golež, Y. Murakami, N. Bittner, A. Herrmann, H. U. Strand, P. Werner, and M. Eckstein, Nessi: The non-equilibrium systems simulation package, Comput. Phys. Commun. 257, 107484 (2020).
  68. J. Kaye and D. Golež, Low rank compression in the numerical solution of the nonequilibrium Dyson equation, SciPost Phys. 10, 091 (2021).

Outline

Information

Phys. Rev. B 111, L121106– Published 18 March, 2025
  • Received 28 March 2024
  • Revised 16 January 2025
  • Accepted 18 February 2025
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation