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Chen S, Leng PL, Konečná A, Modin E, Gutierrez-Amigo M, Vicentini E, Martín-García B, Barra-Burillo M, Niehues I, Maciel Escudero C, Xie XY, Hueso LE, Artacho E, Aizpurua J, Errea I, Vergniory MG, Chuvilin A, Xiu FX, Hillenbrand R. Real-space observation of ultraconfined in-plane anisotropic acoustic terahertz plasmon polaritons. Nat Mater 2023:10.1038/s41563-023-01547-8. [PMID: 37142739 DOI: 10.1038/s41563-023-01547-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/31/2023] [Indexed: 05/06/2023]
Abstract
Thin layers of in-plane anisotropic materials can support ultraconfined polaritons, whose wavelengths depend on the propagation direction. Such polaritons hold potential for the exploration of fundamental material properties and the development of novel nanophotonic devices. However, the real-space observation of ultraconfined in-plane anisotropic plasmon polaritons (PPs)-which exist in much broader spectral ranges than phonon polaritons-has been elusive. Here we apply terahertz nanoscopy to image in-plane anisotropic low-energy PPs in monoclinic Ag2Te platelets. The hybridization of the PPs with their mirror image-by placing the platelets above a Au layer-increases the direction-dependent relative polariton propagation length and the directional polariton confinement. This allows for verifying a linear dispersion and elliptical isofrequency contour in momentum space, revealing in-plane anisotropic acoustic terahertz PPs. Our work shows high-symmetry (elliptical) polaritons on low-symmetry (monoclinic) crystals and demonstrates the use of terahertz PPs for local measurements of anisotropic charge carrier masses and damping.
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Affiliation(s)
- S Chen
- Terahertz Technology Innovation Research Institute, National Basic Science Center-Terahertz Science and Technology Frontier, Terahertz Precision Biomedical Discipline 111 Project, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, China
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - P L Leng
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - A Konečná
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
- Institute of Physical Engineering, Brno University of Technology, Brno, Czech Republic
| | - E Modin
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - M Gutierrez-Amigo
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Departamento de Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Bilbao, Spain
| | - E Vicentini
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - B Martín-García
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | | | - I Niehues
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - C Maciel Escudero
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
| | - X Y Xie
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - L E Hueso
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - E Artacho
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
| | - J Aizpurua
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
| | - I Errea
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, Universidad del País Vasco (UPV/EHU), Donostia-San Sebastián, Spain
| | - M G Vergniory
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
- Max Planck for Chemical Physics of Solids, Dresden, Germany
| | - A Chuvilin
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - F X Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
| | - R Hillenbrand
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia-San Sebastián, Spain.
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