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Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation


Phonon polaritons—light coupled to lattice vibrations—in polar van der Waals crystals are promising candidates for controlling the flow of energy on the nanoscale due to their strong field confinement, anisotropic propagation and ultra-long lifetime in the picosecond range1,2,3,4,5. However, the lack of tunability of their narrow and material-specific spectral range—the Reststrahlen band—severely limits their technological implementation. Here, we demonstrate that intercalation of Na atoms in the van der Waals semiconductor α-V2O5 enables a broad spectral shift of Reststrahlen bands, and that the phonon polaritons excited show ultra-low losses (lifetime of 4 ± 1 ps), similar to phonon polaritons in a non-intercalated crystal (lifetime of 6 ± 1 ps). We expect our intercalation method to be applicable to other van der Waals crystals, opening the door for the use of phonon polaritons in broad spectral bands in the mid-infrared domain.

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Fig. 1: Physical properties of α-V2O5.
Fig. 2: Real-space imaging of a α-V2O5 flake.
Fig. 3: Real-space nano-spectroscopy of α-V2O5 and intercalated α’-(Na)V2O5 flakes.
Fig. 4: PhPs dispersion and ab initio permittivity in α-V2O5 and intercalated α’-(Na)V2O5 crystals.
Fig. 5: Anisotropy and lifetimes of PhPs in α-V2O5 and intercalated α’-(Na)V2O5 flakes.

Data availability

The data represented in Figs. 15 are provided with the paper as source data. All other data that support results in this Letter are available from the corresponding author on reasonable request.

Code availability

The custom code employed in this work to perform all calculations is available from the corresponding authors on reasonable request.


  1. Dai, S. et al. Tunable phonon polaritons in atomically thin van der Waals crystals of boron nitride. Science 343, 1125–1129 (2014).

    Article  CAS  Google Scholar 

  2. Ma, W. et al. In-plane anisotropic and ultra-low-loss polaritons in a natural van der Waals crystal. Nature 562, 557–562 (2018).

    Article  CAS  Google Scholar 

  3. Giles, A. J. et al. Ultralow-loss polaritons in isotopically pure boron nitride. Nat. Mater. 17, 134–139 (2017).

    Article  Google Scholar 

  4. Zheng, Z. et al. Highly confined and tunable hyperbolic phonon polaritons in van der waals semiconducting transition metal oxides. Adv. Mat. 30, 1705318 (2018).

    Article  Google Scholar 

  5. Zheng, Z. et al. A mid-infrared biaxial hyperbolic van der Waals crystal. Sci. Adv. 5, eaav8690 (2019).

    Article  CAS  Google Scholar 

  6. Low, T. et al. Polaritons in layered two-dimensional materials. Nat. Mater. 16, 182 (2016).

    Article  Google Scholar 

  7. Basov, D. N., Fogler, M. M. & García de Abajo, F. J. Polaritons in van der Waals materials. Science 354, aag1992 (2016).

    Article  Google Scholar 

  8. Li, P. et al. Reversible optical switching of highly confined phonon-polaritons with an ultrathin phase-change material. Nat. Mater. 15, 870–875 (2016).

    Article  CAS  Google Scholar 

  9. Sukimura, H. et al. Highly confined and switchable mid-infrared surface phonon polariton resonances of planar circular cavities with a phase change material. Nano Lett. 19, 2549–2554 (2019).

    Article  Google Scholar 

  10. Caldwell, J. D. et al. Photonics with hexagonal boron nitride. Nat. Rev. Mater. 4, 552–567 (2019).

    Article  CAS  Google Scholar 

  11. Dunkelberger, A. D. et al. Active tuning of surface phonon polariton resonances via carrier photoinjection. Nat. Photonics 12, 50–56 (2018).

    Article  CAS  Google Scholar 

  12. Ratchford, D. C. et al. Controlling the infrared dielectric function through atomic-scale heterostructures. ACS Nano 13, 6730–6741 (2019).

    Article  CAS  Google Scholar 

  13. Bhandari, C. & Lambrecht, W. R. L. Phonons and related spectra in bulk and monolayer V2O5. Phys. Rev. B. 89, 045109 (2014).

    Article  Google Scholar 

  14. Sucharitakul, S. et al. V2O5: A 2D van der waals oxide with strong in-plane electrical and optical anisotropy. ACS Appl. Mater. Interfaces 9, 23949–23956 (2017).

    Article  CAS  Google Scholar 

  15. Clauws, P. & Vennik, J. Lattice vibrations of V2O5. Determination of TO and LO frequencies from infrared reflection and transmission. Phys. Status Solidi 76, 707–713 (1976).

    Article  CAS  Google Scholar 

  16. Gomez-Diaz, J. S. & Alù, A. Flatland optics with hyperbolic metasurfaces. ACS Photonics 3, 2211–2224 (2016).

    Article  CAS  Google Scholar 

  17. Gomez-Diaz, J. S., Tymchenko, M. & Alù, A. Hyperbolic plasmons and topological transitions over uniaxial metasurfaces. Phys. Rev. Lett. 114, 233901 (2015).

    Article  Google Scholar 

  18. Chen, J. et al. Optical nano-imaging of gate-tunable graphene plasmons. Nature 487, 77–81 (2012).

    Article  CAS  Google Scholar 

  19. Fei, Z. et al. Gate-tuning of graphene plasmons revealed by infrared nano-imaging. Nature 487, 82–85 (2012).

    Article  CAS  Google Scholar 

  20. Autore, M. et al. Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit. Light.: Sci. Appl. 14, 17172 (2018).

    Article  Google Scholar 

  21. Huth, F., Schnell, M., Wittborn, J., Ocelic, N. & Hillenbrand, R. Infrared-spectroscopic nanoimaging with a thermal source. Nat. Mater. 10, 352–356 (2011).

    Article  CAS  Google Scholar 

  22. Braithwaite, J. S., Catlow, C. R. A., Gale, J. D. & Harding, J. H. Lithium intercalation into vanadium pentoxide: a theoretical study. Chem. Mater. 11, 1990–1998 (1999).

    Article  CAS  Google Scholar 

  23. Liu, J., Xia, H., Xue, D. & Lu, L. Double-shelled nanocapsules of V2O5-based composites as high-performance anode and cathode materials for Li ion batteries. J. Am. Chem. Soc. 131, 12086–12087 (2009).

    Article  CAS  Google Scholar 

  24. Xiong, F. et al. Li intercalation in MoS2: in situ observation of its dynamics and tuning optical and electrical properties. Nano Lett. 15, 6777–6784 (2015).

    Article  CAS  Google Scholar 

  25. Cha, JudyJ. et al. Two-dimensional chalcogenide nanoplates as tunable metamaterials via chemical intercalation. Nano Lett. 13, 5913–5918 (2013).

    Article  CAS  Google Scholar 

  26. Zhang, R., Waters, J., Geim, A. K. & Grigorieva, I. V. Intercalant-independent transition temperature in superconducting black phosphorus. Nat. Commun. 8, 15036 (2017).

    Article  CAS  Google Scholar 

  27. Pons-Valencia, P. et al. Launching of hyperbolic phonon-polaritons in h-BN slabs by resonant metal plasmonic antennas. Nat. Commun. 10, 3242 (2019).

    Article  CAS  Google Scholar 

  28. Woessner, A. et al. Highly confined low-loss plasmons in graphene–boron nitride heterostructures. Nat. Mater. 14, 421–425 (2014).

    Article  Google Scholar 

  29. Kwabena Bediako, D. Heterointerface effects in the electrointercalation of van der Waals heterostuctures. Nature 558, 425–429 (2018).

    Article  Google Scholar 

  30. Talwar, N. T. Direct evidence of LO phonon-plasmons coupled modes in n-GaN. Appl. Phys. Lett. 97, 051902 (2010).

    Article  Google Scholar 

  31. Haemers, J. Purification and single crystal growth of V2O5. Bull. des. Soci. Chim. Belg. 79, 473–477 (1970).

    Article  CAS  Google Scholar 

  32. Isobe, M., Kagami, C. & Ueda, Y. Crystal growth of new spin-Peierls compound NaV2O5. J. Cryst. Growth 181, 314–317 (1997).

    Article  CAS  Google Scholar 

  33. Álvarez-Pérez, G. et al. Infrared permittivity of the biaxial van der Waals semiconductor α-MoO3 from near- and far-field correlative studies. Preprint at (2019).

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J.T.-G. and G.Á.-P. acknowledge support through the Severo Ochoa Program from the Government of the Principality of Asturias (nos. PA-18-PF-BP17-126 and PA-20-PF-BP19-053, respectively). J.M.-S. acknowledges finantial support from the Clarín Programme from the Government of the Principality of Asturias and a Marie Curie-COFUND grant (PA-18-ACB17-29) and the Ramón y Cajal Program from the Government of Spain (RYC2018-026196-I). K.C., X.P.A.G., H.V. and M.H.B. acknowledge the Air Force Office of Scientific Research (AFOSR) grant no. FA 9550-18-1-0030 for funding support. I.E. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (grant no. FIS2016-76617-P). A.Y.N. acknowledges the Spanish Ministry of Science, Innovation and Universities (national project no. MAT2017-88358-C3-3-R) and the Basque Government (grant no. IT1164-19). Q.B. acknowledges the support from Australian Research Council (grant nos. FT150100450, IH150100006 and CE170100039). R.H. acknowledges support from the Spanish Ministry of Economy, Industry, and Competitiveness (national project RTI2018-094830-B-100 and the Project MDM-2016-0618 of the María de Maeztu Units of Excellence Program) and the Basque Goverment (grant no. IT1164-19). P.A.-G. acknowledges support from the European Research Council under starting grant no. 715496, 2DNANOPTICA.

Author information

Authors and Affiliations



P.A.-G. and J.T.-G. conceived the study. P.A.-G. and J.M.-S. supervised the project. J.T.-G. and J.D. carried out the near-field imaging experiments with the help of M.A., S.L. and W.M. G.A.-P., A.B., R.H., Q.B. and A.Y.N. participated in data analysis. P.A.-G. wrote the manuscript with input from J.T.-G., G.A.-P., J.M.-S., A.N., J.D., Q.B., I.E., X.P.A.G., K.C. and R.H. I.E. carried out ab initio calculations. G.A.-P. and A.Y.N. conducted the analytical calculations. K.K., T.K., K.C. and X.P.A.G. contributed to material synthesis and sample preparation. H.V. and M.H.B. performed the transmission electron microscopy characterization. K.C. performed X-ray diffraction indexing and characterization. I.P. contributed to sample fabrication.

Corresponding authors

Correspondence to Javier Martín-Sánchez or Pablo Alonso-González.

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Competing interests

R.H. is cofounder of Neaspec GmbH, a company producing s-SNOM systems, such as the one used in this study. The remaining authors declare no competing interests.

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Supplementary information

Supplementary Information

Supplementary Sections 1–11, Figs. 1–21 and Tables 1–4.

Source data

Source Data Fig. 1

Fig1c.xlsx is an excel file containing the permittivity values of α-V2O5 along the three crystallographic directions.

Source Data Fig. 2

This contains four sheets: Fig2a, Fig2b and Fig2c with the ascii data matrix files of the third harmonic s-SNOM images, and Fig. 2g with the dispersion values.

Source Data Fig. 3

This contains four sheets: Fig3b_100 and Fig3b_001 are the ascii data matrix values of the α-V2O5 nanoFTIR measurements shown in Fig. 3b, and Fig3d_100, and Fig3d_001 are the ascii data matrix values of the α′- NaV2O5 nanoFTIR measurements shown in Fig. 3d.

Source Data Fig. 4

This contains two sheets: Fig4a with six columns corresponding to the measured dispersions for α-V2O5 and α′-NaV2O5 shown in Fig. 4a,b and Fig. 4b with the ab initio calculated permittivity values for α-V2O5 and α′-NaV2O5 shown in Fig. 4b.

Source Data Fig. 5

This contains two sheets: Figure5a corresponding to the s-SNOM measurement of a gold disk on top of a α-V2O5 flake shown in Fig. 5a and Fig. 5b corresponding to the SNOM measurement of a gold disk on top of a α′- NaV2O5 flake shown in Fig. 5b.

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Taboada-Gutiérrez, J., Álvarez-Pérez, G., Duan, J. et al. Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation. Nat. Mater. 19, 964–968 (2020).

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