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

Javier Taboada-Gutiérrez , Gonzalo Álvarez-Pérez , Jiahua Duan , Weiliang Ma , Kyle Crowley , Ivan Prieto (1) , Andrei Bylinkin , Marta Autore , Halyna Volkova (2) , Kenta Kimura , Tsuyoshi Kimura (3) , Marie-Hélène Berger , Shaojuan Li , Qiaoliang Bao , Xuan Gao , Ion Errea (4) , Alexey Nikitin , Rainer Hillenbrand (5) , Javier Martín-Sánchez , Pablo Alonso-González

1 IST Austria - Institute of Science and Technology [Klosterneuburg, Austria]
2 CDM - Centre des Matériaux
3 Graduate School of Engineering, Osaka University
4 Donostia International Physics Center - DIPC (SPAIN)
5 CIC NanoGUNE

Phonon polaritons—light coupled to lattice vibrations—in polar van der Waals crystals are promising candidates for controlling the flow of nergy on the nanoscale due to their strong field confinement, anisotropic propagation and ultralong lifetime in the picosecond range. However, the lack of tunability of their narrow and material-specific spectral range—the Reststrahlen band—severely limits their technological mplementation. 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.

Domaines: Matière Condensée [cond-mat]

Javier Taboada-Gutiérrez, Gonzalo Álvarez-Pérez, Jiahua Duan, Weiliang Ma, Kyle Crowley, et al.. Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation. Nature Materials, 2020, ⟨10.1038/s41563-020-0665-0⟩. ⟨hal-02545392⟩