- Physical Review Journals
All JournalsPhysics Magazine

Physical Review X

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
  • Open Access

Interaction-Driven Topological Transitions in Monolayer TaIrTe4

Jiangxu Li1,*, Jian Tang2,*, Cheng Xu3,*, Louis Primeau1, Thomas Siyuan Ding2, Rahul Soni1, Tiema Qian4, Kenji Watanabe5, Takashi Taniguchi6 et al.

Ni Ni4, Adrian Del Maestro1,7, Qiong Ma2,8,†, and Yang Zhang1,7,9,‡

  • *These authors contributed equally to this work.
  • †Contact author: maqa@bc.edu
  • ‡Contact author: yangzhang@utk.edu
PDF

Phys. Rev. X 16, 031017 – Published 24 July, 2026

DOI: https://doi.org/10.1103/456g-q7bd

Abstract

Discovering materials that combine topological phenomena with correlated electron behavior is a central pursuit in quantum materials research. Monolayer TaIrTe4 has recently emerged as a promising platform in this context, hosting robust quantum spin Hall insulator (QSHI) phases both within a single-particle gap and within a correlation-induced gap arising from van Hove singularities (vHSs), accessed via electrostatic doping. Its intrinsic monolayer nature offers exceptional tunability and the potential to realize a rich variety of interaction-driven topological phases. In this work, we combine theory and experiment to map the phase landscape of monolayer TaIrTe4. Using Hartree-Fock calculations, we investigate the interaction-driven phase diagram near the vHSs under commensurate filling conditions. By systematically tuning the dielectric screening and strain, we uncover a rich set of ground states—including QSHI, trivial insulator, higher-order topological insulator, and metallic phase—among which are interaction-driven topological phase transitions. Experimentally, we perform local and nonlocal transport measurements across a broad set of devices. Because of unavoidable strain variations during fabrication, the devices exhibit several distinct transport regimes, whose evolution is consistent with the theoretically predicted phase diagram. Finally, band-projected exact diagonalization together with insulating transport features at fractional fillings provide preliminary signatures consistent with a time-reversal-symmetric fractional QSHI in this system. Together, our results lay the groundwork for understanding correlation-driven topological phenomena in TaIrTe4 and open new directions for engineering exotic quantum phases in low-dimensional materials beyond the limitations of moiré superlattices.

View figure in article

Physics Subject Headings (PhySH)

Popular Summary

Identifying materials that combine topological order with strong electron interactions is a primary goal in quantum materials research, since stabilizing such exotic states has usually required complex, artificially engineered moiré structures. We addressed this challenge through a comprehensive theoretical and experimental study of monolayer TaIrTe4. Its electronic structure contains van Hove singularities, energies where electronic states pile up and sharply amplify interactions when reached by applying a voltage. Using Hartree-Fock and exact diagonalization simulations, we mapped a diverse phase diagram including metallic states, ordinary and topological insulators, higher-order topological insulators and fractional quantum spin Hall insulator, all controlled by subtle changes in mechanical strain and dielectric screening. Transport measurements across more than 100 devices confirmed that these interaction-driven phases emerge from the slight strain variations introduced during standard fabrication. The results show that intrinsic crystals can achieve the same topological tunability as twisted heterostructures, establishing a simpler platform for engineering correlated topological states and designing next-generation quantum components.

Article Text

References (59)

  1. D. Hsieh, D. Qian, L. Wray, Y. Xia, Y. S. Hor, R. J. Cava, and M. Z. Hasan, A topological Dirac insulator in a quantum spin Hall phase, Nature (London) 452, 970 (2008).
  2. Y. Chen, J. G. Analytis, J.-H. Chu, Z. Liu, S.-K. Mo, X.-L. Qi, H. Zhang, D. Lu, X. Dai, Z. Fang et al., Experimental realization of a three-dimensional topological insulator, Bi2Te3, Science 325, 178 (2009).
  3. Y. Xia, D. Qian, D. Hsieh, L. Wray, A. Pal, H. Lin, A. Bansil, D. Grauer, Y. S. Hor, R. J. Cava et al., Observation of a large-gap topological-insulator class with a single Dirac cone on the surface, Nat. Phys. 5, 398 (2009).
  4. J. Tang, T. S. Ding, H. Chen, A. Gao, T. Qian, Z. Huang, Z. Sun, X. Han, A. Strasser, J. Li et al., Dual quantum spin Hall insulator by density-tuned correlations in TaIrTe4, Nature (London) 628, 515 (2024).
  5. V. Fatemi, S. Wu, Y. Cao, L. Bretheau, Q. D. Gibson, K. Watanabe, T. Taniguchi, R. J. Cava, and P. Jarillo-Herrero, Electrically tunable low-density superconductivity in a monolayer topological insulator, Science 362, 926 (2018).
  6. K. Kang, B. Shen, Y. Qiu, Y. Zeng, Z. Xia, K. Watanabe, T. Taniguchi, J. Shan, and K. F. Mak, Evidence of the fractional quantum spin Hall effect in moiré MoTe2, Nature (London) 628, 522 (2024).
  7. K. Kang, Y. Qiu, B. Shen, K. Lee, Z. Xia, Y. Zeng, K. Watanabe, T. Taniguchi, J. Shan, and K. F. Mak, Time-reversal symmetry breaking fractional quantum spin Hall insulator in moiré MoTe2, arXiv:2501.02525.
  8. J. Tang, T. S. Ding, S. Ding, J. Li, C. Yi, T. Tang, Z. Huang, X. Wu, Z. Huang, B. Singh et al., Bistable superlattice switching in a quantum spin Hall insulator, Nature (London) 652, 1 (2026).
  9. J. Cai, E. Anderson, C. Wang, X. Zhang, X. Liu, W. Holtzmann, Y. Zhang, F. Fan, T. Taniguchi, K. Watanabe et al., Signatures of fractional quantum anomalous Hall states in twisted MoTe2, Nature (London) 622, 63 (2023).
  10. H. Park, J. Cai, E. Anderson, Y. Zhang, J. Zhu, X. Liu, C. Wang, W. Holtzmann, C. Hu, Z. Liu et al., Observation of fractionally quantized anomalous Hall effect, Nature (London) 622, 74 (2023).
  11. Y. Zeng, Z. Xia, K. Kang, J. Zhu, P. Knüppel, C. Vaswani, K. Watanabe, T. Taniguchi, K. F. Mak, and J. Shan, Thermodynamic evidence of fractional Chern insulator in moiré MoTe2, Nature (London) 622, 69 (2023).
  12. F. Xu, Z. Sun, T. Jia, C. Liu, C. Xu, C. Li, Y. Gu, K. Watanabe, T. Taniguchi, B. Tong et al., Observation of Integer and Fractional Quantum Anomalous Hall Effects in Twisted Bilayer MoTe2, Phys. Rev. X 13, 031037 (2023).
  13. Z. Lu, T. Han, Y. Yao, A. P. Reddy, J. Yang, J. Seo, K. Watanabe, T. Taniguchi, L. Fu, and L. Ju, Fractional quantum anomalous Hall effect in multilayer graphene, Nature (London) 626, 759 (2024).
  14. A. P. Reddy, N. Paul, A. Abouelkomsan, and L. Fu, Non-Abelian Fractionalization in Topological Minibands, Phys. Rev. Lett. 133, 166503 (2024).
  15. C. Xu, N. Mao, T. Zeng, and Y. Zhang, Multiple Chern Bands in Twisted MoTe2 and Possible Non-Abelian States, Phys. Rev. Lett. 134, 066601 (2025).
  16. C.-E. Ahn, W. Lee, K. Yananose, Y. Kim, and G. Y. Cho, Non-Abelian fractional quantum anomalous Hall states and first Landau level physics of the second moiré band of twisted bilayer MoTe2, Phys. Rev. B 110, L161109 (2024).
  17. C. Wang, X.-W. Zhang, X. Liu, J. Wang, T. Cao, and D. Xiao, Higher Landau-Level Analogs and Signatures of Non-Abelian States in Twisted Bilayer MoTe2, Phys. Rev. Lett. 134, 076503 (2025).
  18. Z. Jiang, Z. Liu, H. Ma, W. Xia, Z. Liu, J. Liu, S. Cho, Y. Yang, J. Ding, J. Liu et al., Flat bands, non-trivial band topology and rotation symmetry breaking in layered kagome-lattice RbTi3Bi5, Nat. Commun. 14, 4892 (2023).
  19. C. Farhang, N. Zaki, J. Wang, G. Gu, P. D. Johnson, and J. Xia, Revealing the Origin of Time-Reversal Symmetry Breaking in Fe-Chalcogenide Superconductor FeTe1−xSex, Phys. Rev. Lett. 130, 046702 (2023).
  20. D. R. Saykin, C. Farhang, E. D. Kountz, D. Chen, B. R. Ortiz, C. Shekhar, C. Felser, S. D. Wilson, R. Thomale, J. Xia et al., High resolution polar Kerr effect studies of CsV3Sb5: Tests for time-reversal symmetry breaking below the charge-order transition, Phys. Rev. Lett. 131, 016901 (2023).
  21. C. Farhang, J. Wang, B. R. Ortiz, S. D. Wilson, and J. Xia, Unconventional specular optical rotation in the charge ordered state of Kagome metal CsV3Sb5, Nat. Commun. 14, 5326 (2023).
  22. X. Teng, L. Chen, F. Ye, E. Rosenberg, Z. Liu, J.-X. Yin, Y.-X. Jiang, J. S. Oh, M. Z. Hasan, K. J. Neubauer et al., Discovery of charge density wave in a kagome lattice antiferromagnet, Nature (London) 609, 490 (2022).
  23. Y. Li, M. Liu, J. Li, J. Wang, J. Lai, D. He, R. Qiu, Y. Sun, X.-Q. Chen, and P. Liu, Origin of the charge density wave state in BaFe2Al9, Phys. Rev. B 110, 195118 (2024).
  24. M. R. Slot, T. S. Gardenier, P. H. Jacobse, G. C. Van Miert, S. N. Kempkes, S. J. Zevenhuizen, C. M. Smith, D. Vanmaekelbergh, and I. Swart, Experimental realization and characterization of an electronic Lieb lattice, Nat. Phys. 13, 672 (2017).
  25. W. Jiang, M. Kang, H. Huang, H. Xu, T. Low, and F. Liu, Topological band evolution between Lieb and kagome lattices, Phys. Rev. B 99, 125131 (2019).
  26. B. Cui, X. Zheng, J. Wang, D. Liu, S. Xie, and B. Huang, Realization of Lieb lattice in covalent-organic frameworks with tunable topology and magnetism, Nat. Commun. 11, 66 (2020).
  27. A. K. Nayak, J. Reiner, H. Tan, H. Fu, H. Ling, C. Shekhar, C. Felser, T. T. Pereg-Barnea, B. Yan, H. Beidenkopf et al., Visualizing near-coexistence of massless Dirac electrons and ultra-massive saddle point electrons, SciPost Phys. 15, 178 (2023).
  28. S. Li, X. Shi, J. Li, C. He, T. Ouyang, C. Tang, and J. Zhong, Spin-orbital coupling induced isolated flat band in bismuthene with k-dependent spin texture, Phys. Rev. B 110, 115115 (2024).
  29. H. Tan and B. Yan, Disordered charge density waves in the kagome metal FeGe, Phys. Rev. B 111, 045160 (2025).
  30. X. Qian, J. Liu, L. Fu, and J. Li, Quantum spin Hall effect in two-dimensional transition metal dichalcogenides, Science 346, 1344 (2014).
  31. X. Liu, J. Lai, J. Zhan, T. Yu, W. Shi, P. Liu, X.-Q. Chen, and Y. Sun, Prediction of the Dual Quantum Spin Hall Insulator in the NbIrTe4 Monolayer, Chin. Phys. Lett. 42, 037302 (2025).
  32. J. Lai, X. Liu, J. Zhan, T. Yu, P. Liu, X.-Q. Chen, and Y. Sun, Switchable Quantized Signal between Longitudinal Conductance and Hall Conductance in Dual Quantum Spin Hall Insulator TaIrTe4, Research 7, 0439 (2024).
  33. W. Kohn and L. J. Sham, Self-Consistent Equations Including Exchange and Correlation Effects, Phys. Rev. 140, A1133 (1965).
  34. C. Xu, J. Li, Y. Xu, Z. Bi, and Y. Zhang, Maximally localized Wannier functions, interaction models, and fractional quantum anomalous Hall effect in twisted bilayer MoTe2, Proc. Natl. Acad. Sci. U.S.A. 121, e2316749121 (2024).
  35. X. Lu, S. Zhang, Y. Wang, X. Gao, K. Yang, Z. Guo, Y. Gao, Y. Ye, Z. Han, and J. Liu, Synergistic correlated states and nontrivial topology in coupled graphene-insulator heterostructures, Nat. Commun. 14, 5550 (2023).
  36. X. Huang, J. L. Lado, J. Sainio, P. Liljeroth, and S. C. Ganguli, Doped Mott Phase and Charge Correlations in Monolayer 1T−NbSe2, Phys. Rev. Lett. 134, 046504 (2025).
  37. C. Zhao, M. Hu, J. Qin, B. Xia, C. Liu, S. Wang, D. D. Guan, Y. Li, H. Zheng, J. Liu, and J. Jia, Strain Tunable Semimetal–Topological-Insulator Transition in Monolayer 1T′−WTe2, Phys. Rev. Lett. 125, 046801 (2020).
  38. J. Liu, Y. Zhou, S. Yepez Rodriguez, M. A. Delmont, R. A. Welser, T. Ho, N. Sirica, K. McClure, P. Vilmercati, J. W. Ziller et al., Controllable strain-driven topological phase transition and dominant surface-state transport in HfTe5, Nat. Commun. 15, 332 (2024).
  39. H. Jiang, T. Xi, J. Li, Y. He, H. Ma, Y. Mao, T. Taniguchi, K. Watanabe, D. A. Rhodes, Y. Zhang et al., Probing interplay of topological properties and electron correlation in TaIrTe4 via nonlinear Hall effect, Nat. Commun. 16, 6351 (2025).
  40. T. Xi, H. Jiang, J. Li, Y. He, Y. Gu, C. Fox, L. Primeau, Y. Mao, J. Rollins, T. Taniguchi et al., Terahertz sensing based on the nonlinear electrodynamics of the two-dimensional correlated topological semimetal TaIrTe4, Natl. Electron. Rev. 8, 578 (2025).
  41. J. Liu, H. Wang, C. Fang, L. Fu, and X. Qian, van der Waals stacking-induced topological phase transition in layered ternary transition metal chalcogenides, Nano Lett. 17, 467 (2017).
  42. H. Zhou, D. Alexander, and K. Lange, A quasi-Newton acceleration for high-dimensional optimization algorithms, Stat. Comput. 21, 261 (2011).
  43. A. P. Schnyder, S. Ryu, A. Furusaki, and Andreas W. W. Ludwig, Classification of topological insulators and superconductors in three spatial dimensions, Phys. Rev. B 78, 195125 (2008).
  44. J. Cenker, S. Sivakumar, K. Xie, A. Miller, P. Thijssen, Z. Liu, A. Dismukes, J. Fonseca, E. Anderson, X. Zhu et al., Reversible strain-induced magnetic phase transition in a van der Waals magnet, Nat. Nanotechnol. 17, 256 (2022).
  45. J. Cenker, D. Ovchinnikov, H. Yang, D. G. Chica, C. Zhu, J. Cai, G. Diederich, Z. Liu, X. Zhu, X. Roy et al., Strain-programmable van der Waals magnetic tunnel junctions, Newton 1, 100130 (2025).
  46. K. Hwangbo, E. Rosenberg, J. Cenker, Q. Jiang, H. Wen, D. Xiao, J.-H. Chu, and X. Xu, Strain tuning of vestigial three-state Potts nematicity in a correlated antiferromagnet, Nat. Phys. 20, 1888 (2024).
  47. Z. Liu, X. Ma, J. Cenker, J. Cai, Z. Fei, P. Malinowski, J. Mutch, Y. Zhao, K. Hwangbo, Z. Lin et al., Continuously tunable uniaxial strain control of van der Waals heterostructure devices, J. Appl. Phys. 135, 204306 (2024).
  48. J. Cenker, J. Fonseca, M. Nguyen, C. Hu, D. G. Chica, T. Taniguchi, K. Watanabe, X. Zhu, X. Roy, J.-H. Chu et al., Engineering robust strain transmission in van der Waals heterostructure devices, Nano Lett. 25, 4512 (2025).
  49. Z. Fei, T. Palomaki, S. Wu, W. Zhao, X. Cai, B. Sun, P. Nguyen, J. Finney, X. Xu, and D. H. Cobden, Edge conduction in monolayer WTe2, Nat. Phys. 13, 677 (2017).
  50. M. Levin and A. Stern, Fractional topological insulators, Phys. Rev. Lett. 103, 196803 (2009).
  51. T. Neupert, L. Santos, C. Chamon, and C. Mudry, Fractional Quantum Hall States at Zero Magnetic Field, Phys. Rev. Lett. 106, 236804 (2011).
  52. S. Cai, E. Emmanouilidou, J. Guo, X. Li, Y. Li, K. Yang, A. Li, Q. Wu, N. Ni, and L. Sun, Observation of superconductivity in the pressurized Weyl-semimetal candidate TaIrTe4 Phys. Rev. B 99, 020503(R) (2019).
  53. C. Nayak, S. H. Simon, A. Stern, M. Freedman, and S. Das Sarma, Non-Abelian anyons and topological quantum computation, Rev. Mod. Phys. 80, 1083 (2008).
  54. M. L. Sancho, J. L. Sancho, J. L. Sancho, and J. Rubio, Non-Abelian anyons and topological quantum computation, J. Phys. F 15, 851 (1985).
  55. H.-X. Wang, G.-Y. Guo, and J.-H. Jiang, Band topology in classical waves: Wilson-loop approach to topological numbers and fragile topology, New J. Phys. 21, 093029 (2019).
  56. R. Yu, X. L. Qi, A. Bernevig, Z. Fang, and X. Dai, Equivalent expression of Z2 topological invariant for band insulators using the non-Abelian Berry connection, Phys. Rev. B 84, 075119 (2011).
  57. C. L. Kane and E. J. Mele, Z2 Topological Order and the Quantum Spin Hall Effect, Phys. Rev. Lett. 95, 146802 (2005).
  58. L. Fu and C. L. Kane, Topological insulators with inversion symmetry, Phys. Rev. B 76, 045302 (2007).
  59. P. Zhang, P. Richard, T. Qian, Y.-M. Xu, X. Dai, and H. Ding, A precise method for visualizing dispersive features in image plots, Rev. Sci. Instrum. 82, 043712 (2011).

Outline

Information

Phys. Rev. X 16, 031017– Published 24 July, 2026
  • Received 7 July 2025
  • Revised 26 February 2026
  • Accepted 18 May 2026
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