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Nörenberg T, Álvarez-Pérez G, Obst M, Wehmeier L, Hempel F, Klopf JM, Nikitin AY, Kehr SC, Eng LM, Alonso-González P, de Oliveira TVAG. Germanium Monosulfide as a Natural Platform for Highly Anisotropic THz Polaritons. ACS NANO 2022; 16:20174-20185. [PMID: 36446407 PMCID: PMC9799068 DOI: 10.1021/acsnano.2c05376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 11/08/2022] [Indexed: 05/17/2023]
Abstract
Terahertz (THz) electromagnetic radiation is key to access collective excitations such as magnons (spins), plasmons (electrons), or phonons (atomic vibrations), thus bridging topics between optics and solid-state physics. Confinement of THz light to the nanometer length scale is desirable for local probing of such excitations in low-dimensional systems, thereby circumventing the large footprint and inherently low spectral power density of far-field THz radiation. For that purpose, phonon polaritons (PhPs) in anisotropic van der Waals (vdW) materials have recently emerged as a promising platform for THz nanooptics. Hence, there is a demand for the exploration of materials that feature not only THz PhPs at different spectral regimes but also host anisotropic (directional) electrical, thermoelectric, and vibronic properties. To that end, we introduce here the semiconducting vdW-material alpha-germanium(II) sulfide (GeS) as an intriguing candidate. By employing THz nanospectroscopy supported by theoretical analysis, we provide a thorough characterization of the different in-plane hyperbolic and elliptical PhP modes in GeS. We find not only PhPs with long lifetimes (τ > 2 ps) and excellent THz light confinement (λ0/λ > 45) but also an intrinsic, phonon-induced anomalous dispersion as well as signatures of naturally occurring, substrate-mediated PhP canalization within a single GeS slab.
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Affiliation(s)
- Tobias Nörenberg
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
- Würzburg-Dresden
Cluster of Excellence - EXC 2147 (ct.qmat), Dresden 01062, Germany
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Gonzalo Álvarez-Pérez
- Department of Physics, University
of Oviedo, Oviedo 33006, Spain
- Center of Research
on Nanomaterials and Nanotechnology CINN (CSIC−Universidad
de Oviedo), El Entrego 33940, Spain
| | - Maximilian Obst
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
| | - Lukas Wehmeier
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
- Würzburg-Dresden
Cluster of Excellence - EXC 2147 (ct.qmat), Dresden 01062, Germany
| | - Franz Hempel
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
- Collaborative Research
Center 1415, Technische Universität
Dresden, Dresden 01069, Germany
| | - J. Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Alexey Y. Nikitin
- Donostia International
Physics Center (DIPC), Donostia-San
Sebastián 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Susanne C. Kehr
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
| | - Lukas M. Eng
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
- Würzburg-Dresden
Cluster of Excellence - EXC 2147 (ct.qmat), Dresden 01062, Germany
- Collaborative Research
Center 1415, Technische Universität
Dresden, Dresden 01069, Germany
| | - Pablo Alonso-González
- Department of Physics, University
of Oviedo, Oviedo 33006, Spain
- Center of Research
on Nanomaterials and Nanotechnology CINN (CSIC−Universidad
de Oviedo), El Entrego 33940, Spain
| | - Thales V. A. G. de Oliveira
- Institut für
Angewandte Physik, Technische Universität
Dresden, Dresden 01187, Germany
- Würzburg-Dresden
Cluster of Excellence - EXC 2147 (ct.qmat), Dresden 01062, Germany
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
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Kim HS, Ha NY, Park JY, Lee S, Kim DS, Ahn YH. Phonon-Polaritons in Lead Halide Perovskite Film Hybridized with THz Metamaterials. NANO LETTERS 2020; 20:6690-6696. [PMID: 32786930 DOI: 10.1021/acs.nanolett.0c02572] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, we demonstrated a phonon-polariton in the terahertz (THz) frequency range, generated in a crystallized lead halide perovskite film coated on metamaterials. When the metamaterial resonance was in tune with the phonon resonance of the perovskite film, Rabi splitting occurred due to the strong coupling between the resonances. The Rabi splitting energy was about 1.1 meV, which is larger than the metamaterial and phonon resonance line widths; the interaction potential estimation confirmed that the strong coupling regime was reached successfully. We were able to tune the polaritonic branches by varying the metamaterial resonance, thereby obtaining the dispersion curve with a clear anticrossing behavior. Additionally, we performed in situ THz spectroscopy as we annealed the perovskite film and studied the Rabi splitting as a function of the films' crystallization coverage. The Rabi splitting versus crystallization volume fraction exhibited a unique power-law scaling, depending on the crystal growth dimensions.
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Affiliation(s)
- Hwan Sik Kim
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
| | - Na Young Ha
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
| | - Ji-Yong Park
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
| | - Soonil Lee
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
| | - Dai-Sik Kim
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Yeong Hwan Ahn
- Department of Physics and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea
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Paschos GG, Tzimis A, Tsintzos SI, Savvidis PG. Polariton condensate trapping by parametric pair scattering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:36LT02. [PMID: 32396883 DOI: 10.1088/1361-648x/ab9267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
Spatially confined, trapped polariton condensates have been shown to exhibit strong stochastic on-site spin polarization and in longer polariton condensate chains, distance controlled ferromagnetic and antiferromagnetic spin couplings. Until now, little is known, on how such polariton condensates spatially separated from their exciton reservoirs are trapped and formed. Here, we investigate the properties and formation dynamics of two main families of polariton condensates, those overlapping with the pump reservoir and those in confined geometries, under pulsed nonresonant excitation. The observed reduction in polariton condensation threshold and energy blueshift in trapped case is attributed to exciton reservoir-condensate spatial separation, whereas time-resolved photoluminescence measurements, reveal distinct relaxation and condensate formation dynamics with pair parametric scattering process being the dominant relaxation mechanism in trapped geometry.
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Affiliation(s)
- G G Paschos
- Westlake University, 18 Shilongshan Rd, Hangzhou 310024, Zhejiang, People's Republic of China
- Westlake Inst Adv Study, National Institute of Sciences, 18 Shilongshan Rd, Hangzhou 310024, Zhejiang, People's Republic of China
- Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, 71110 Heraklion, Crete, Greece
| | - A Tzimis
- Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, 71110 Heraklion, Crete, Greece
| | - S I Tsintzos
- Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, 71110 Heraklion, Crete, Greece
- Eulambia Advanced Technologies Ltd., Ag. Ioannou 24, 15342, Athens, Greece
| | - P G Savvidis
- Westlake University, 18 Shilongshan Rd, Hangzhou 310024, Zhejiang, People's Republic of China
- Westlake Inst Adv Study, National Institute of Sciences, 18 Shilongshan Rd, Hangzhou 310024, Zhejiang, People's Republic of China
- Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, 71110 Heraklion, Crete, Greece
- Department of Nanophotonics and Metamaterials, ITMO University, 197101 St. Petersburg, Russia
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