Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope

Handle URI:
http://hdl.handle.net/10754/625259
Title:
Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope
Authors:
Govyadinov, Alexander A.; Konečná, Andrea; Chuvilin, Andrey ( 0000-0002-3712-5638 ) ; Vélez, Saül; Dolado, Irene; Nikitin, Alexey Y. ( 0000-0002-2327-0164 ) ; Lopatin, Sergei ( 0000-0003-3916-3803 ) ; Casanova, Fèlix; Hueso, Luis E. ( 0000-0002-7918-8047 ) ; Aizpurua, Javier; Hillenbrand, Rainer
Abstract:
Van der Waals materials exhibit intriguing structural, electronic, and photonic properties. Electron energy loss spectroscopy within scanning transmission electron microscopy allows for nanoscale mapping of such properties. However, its detection is typically limited to energy losses in the eV range-too large for probing low-energy excitations such as phonons or mid-infrared plasmons. Here, we adapt a conventional instrument to probe energy loss down to 100 meV, and map phononic states in hexagonal boron nitride, a representative van der Waals material. The boron nitride spectra depend on the flake thickness and on the distance of the electron beam to the flake edges. To explain these observations, we developed a classical response theory that describes the interaction of fast electrons with (anisotropic) van der Waals slabs, revealing that the electron energy loss is dominated by excitation of hyperbolic phonon polaritons, and not of bulk phonons as often reported. Thus, our work is of fundamental importance for interpreting future low-energy loss spectra of van der Waals materials.Here the authors adapt a STEM-EELS system to probe energy loss down to 100 meV, and apply it to map phononic states in hexagonal boron nitride, revealing that the electron loss is dominated by hyperbolic phonon polaritons.
KAUST Department:
Imaging and Characterization Core Lab
Citation:
Govyadinov AA, Konečná A, Chuvilin A, Vélez S, Dolado I, et al. (2017) Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope. Nature Communications 8. Available: http://dx.doi.org/10.1038/s41467-017-00056-y.
Publisher:
Springer Nature
Journal:
Nature Communications
Issue Date:
14-Jul-2017
DOI:
10.1038/s41467-017-00056-y
Type:
Article
ISSN:
2041-1723
Sponsors:
We acknowledge financial support from the European Commission under the Graphene Flagship (GrapheneCore1, grant no. 696656), the ERC starting grant SPINTROS (grant no. 257654), and the Spanish Ministry of Economy and Competitiveness (National plans MAT2014-53432-C5-4-R, MAT2015-65159-R, MAT2015-65525-R, and FIS2016-80174-P). A.K. also thanks for the Czechoslovak Microscopic Society/FEI scholarship. We are also greatly thankful to S. Mastel for AFM measurements of the h-BN flake thickness.
Additional Links:
https://www.nature.com/articles/s41467-017-00056-y
Appears in Collections:
Articles; Advanced Nanofabrication, Imaging and Characterization Core Lab

Full metadata record

DC FieldValue Language
dc.contributor.authorGovyadinov, Alexander A.en
dc.contributor.authorKonečná, Andreaen
dc.contributor.authorChuvilin, Andreyen
dc.contributor.authorVélez, Saülen
dc.contributor.authorDolado, Ireneen
dc.contributor.authorNikitin, Alexey Y.en
dc.contributor.authorLopatin, Sergeien
dc.contributor.authorCasanova, Fèlixen
dc.contributor.authorHueso, Luis E.en
dc.contributor.authorAizpurua, Javieren
dc.contributor.authorHillenbrand, Raineren
dc.date.accessioned2017-07-26T06:19:10Z-
dc.date.available2017-07-26T06:19:10Z-
dc.date.issued2017-07-14en
dc.identifier.citationGovyadinov AA, Konečná A, Chuvilin A, Vélez S, Dolado I, et al. (2017) Probing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscope. Nature Communications 8. Available: http://dx.doi.org/10.1038/s41467-017-00056-y.en
dc.identifier.issn2041-1723en
dc.identifier.doi10.1038/s41467-017-00056-yen
dc.identifier.urihttp://hdl.handle.net/10754/625259-
dc.description.abstractVan der Waals materials exhibit intriguing structural, electronic, and photonic properties. Electron energy loss spectroscopy within scanning transmission electron microscopy allows for nanoscale mapping of such properties. However, its detection is typically limited to energy losses in the eV range-too large for probing low-energy excitations such as phonons or mid-infrared plasmons. Here, we adapt a conventional instrument to probe energy loss down to 100 meV, and map phononic states in hexagonal boron nitride, a representative van der Waals material. The boron nitride spectra depend on the flake thickness and on the distance of the electron beam to the flake edges. To explain these observations, we developed a classical response theory that describes the interaction of fast electrons with (anisotropic) van der Waals slabs, revealing that the electron energy loss is dominated by excitation of hyperbolic phonon polaritons, and not of bulk phonons as often reported. Thus, our work is of fundamental importance for interpreting future low-energy loss spectra of van der Waals materials.Here the authors adapt a STEM-EELS system to probe energy loss down to 100 meV, and apply it to map phononic states in hexagonal boron nitride, revealing that the electron loss is dominated by hyperbolic phonon polaritons.en
dc.description.sponsorshipWe acknowledge financial support from the European Commission under the Graphene Flagship (GrapheneCore1, grant no. 696656), the ERC starting grant SPINTROS (grant no. 257654), and the Spanish Ministry of Economy and Competitiveness (National plans MAT2014-53432-C5-4-R, MAT2015-65159-R, MAT2015-65525-R, and FIS2016-80174-P). A.K. also thanks for the Czechoslovak Microscopic Society/FEI scholarship. We are also greatly thankful to S. Mastel for AFM measurements of the h-BN flake thickness.en
dc.publisherSpringer Natureen
dc.relation.urlhttps://www.nature.com/articles/s41467-017-00056-yen
dc.rightsThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleProbing low-energy hyperbolic polaritons in van der Waals crystals with an electron microscopeen
dc.typeArticleen
dc.contributor.departmentImaging and Characterization Core Laben
dc.identifier.journalNature Communicationsen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionCIC nanoGUNE, 20018, Donostia-San Sebastián, Spain.en
dc.contributor.institutionMaterials Physics Center, CSIC-UPV/EHU, 20018, Donostia-San Sebastián, Spain.en
dc.contributor.institutionIKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.en
dc.contributor.institutionDonostia International Physics Center DIPC, 20018, Donostia-San Sebastián, Spain.en
dc.contributor.institutionCIC nanoGUNE and UPV/EHU, 20018, Donostia-San Sebastián, Spain.en
kaust.authorLopatin, Sergeien
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