1
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Wehmeier L, Yu SJ, Chen X, Mayer RA, Xiong L, Yao H, Jiang Y, Hu J, Janzen E, Edgar JH, Zheng X, Heinz TF, Basov DN, Homes CC, Hu G, Carr GL, Liu M, Fan JA. Tunable Phonon Polariton Hybridization in a van der Waals Hetero-Bicrystal. Adv Mater 2024:e2401349. [PMID: 38657644 DOI: 10.1002/adma.202401349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/05/2024] [Indexed: 04/26/2024]
Abstract
Phonon polaritons, the hybrid quasiparticles resulting from the coupling of photons and lattice vibrations, have gained significant attention in the field of layered van der Waals heterostructures. Particular interest has been paid to hetero-bicrystals composed of molybdenum oxide (MoO3) and hexagonal boron nitride (hBN), which feature polariton dispersion tailorable via avoided polariton mode crossings. In this work, we systematically study the polariton eigenmodes in MoO3-hBN hetero-bicrystals self-assembled on ultrasmooth gold using synchrotron infrared nanospectroscopy. We experimentally demonstrate that the spectral gap in bicrystal dispersion and corresponding regimes of negative refraction can be tuned by material layer thickness, and we quantitatively match these results with a simple analytic model. We also investigate polaritonic cavity modes and polariton propagation along "forbidden" directions in our microscale bicrystals, which arise from the finite in-plane dimension of the synthesized MoO3 micro-ribbons. Our findings shed light on the unique dispersion properties of polaritons in van der Waals heterostructures and pave the way for applications leveraging deeply sub-wavelength mid-infrared light matter interactions. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Lukas Wehmeier
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Shang-Jie Yu
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- Tim Taylor Department of Chemical Engineering, Durland Hall, Kansas State University, Manhattan, KS, 66506, USA
| | - Xinzhong Chen
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
- Department of Physics, Columbia University, New York, New York, 10027, USA
| | - Rafael A Mayer
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Langlang Xiong
- Nanyang Technological University, School of Electrical and Electronic Engineering, Singapore, 637371, Singapore
| | - Helen Yao
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Yue Jiang
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Jenny Hu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Eli Janzen
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - James H Edgar
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Xiaolin Zheng
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Tony F Heinz
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, New York, 10027, USA
| | - Christopher C Homes
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Guangwei Hu
- Nanyang Technological University, School of Electrical and Electronic Engineering, Singapore, 637371, Singapore
| | - G Lawrence Carr
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Mengkun Liu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Jonathan A Fan
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- Tim Taylor Department of Chemical Engineering, Durland Hall, Kansas State University, Manhattan, KS, 66506, USA
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2
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Wehmeier L, Liu M, Park S, Jang H, Basov DN, Homes CC, Carr GL. Ultrabroadband Terahertz Near-Field Nanospectroscopy with a HgCdTe Detector. ACS Photonics 2023; 10:4329-4339. [PMID: 38145170 PMCID: PMC10739990 DOI: 10.1021/acsphotonics.3c01148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/27/2023] [Accepted: 11/01/2023] [Indexed: 12/26/2023]
Abstract
While near-field infrared nanospectroscopy provides a powerful tool for nanoscale material characterization, broadband nanospectroscopy of elementary material excitations in the single-digit terahertz (THz) range remains relatively unexplored. Here, we study liquid-Helium-cooled photoconductive Hg1-XCdXTe (MCT) for use as a fast detector in near-field nanospectroscopy. Compared to the common T = 77 K operation, liquid-Helium cooling reduces the MCT detection threshold to ∼22 meV, improves the noise performance, and yields a response bandwidth exceeding 10 MHz. These improved detector properties have a profound impact on the near-field technique, enabling unprecedented broadband nanospectroscopy across a range of 5 to >50 THz (175 to >1750 cm-1, or <6 to 57 μm), i.e., covering what is commonly known as the "THz gap". Our approach has been implemented as a user program at the National Synchrotron Light Source II, Upton, USA, where we showcase ultrabroadband synchrotron nanospectroscopy of phonons in ZnSe (∼7.8 THz) and BaF2 (∼6.7 THz), as well as hyperbolic phonon polaritons in GeS (6-8 THz).
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Affiliation(s)
- Lukas Wehmeier
- National
Synchrotron Light Source II, Brookhaven
National Laboratory; Upton, New York 11973, United States
- Department
of Physics and Astronomy, Stony Brook University; Stony Brook, New York 11794, United States
| | - Mengkun Liu
- National
Synchrotron Light Source II, Brookhaven
National Laboratory; Upton, New York 11973, United States
- Department
of Physics and Astronomy, Stony Brook University; Stony Brook, New York 11794, United States
| | - Suji Park
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - Houk Jang
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - D. N. Basov
- Department
of Physics, Columbia University; New York, New York 10027, United States
| | - Christopher C. Homes
- National
Synchrotron Light Source II, Brookhaven
National Laboratory; Upton, New York 11973, United States
| | - G. Lawrence Carr
- National
Synchrotron Light Source II, Brookhaven
National Laboratory; Upton, New York 11973, United States
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3
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Dapolito M, Tsuneto M, Zheng W, Wehmeier L, Xu S, Chen X, Sun J, Du Z, Shao Y, Jing R, Zhang S, Bercher A, Dong Y, Halbertal D, Ravindran V, Zhou Z, Petrovic M, Gozar A, Carr GL, Li Q, Kuzmenko AB, Fogler MM, Basov DN, Du X, Liu M. Infrared nano-imaging of Dirac magnetoexcitons in graphene. Nat Nanotechnol 2023; 18:1409-1415. [PMID: 37605044 DOI: 10.1038/s41565-023-01488-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/17/2023] [Indexed: 08/23/2023]
Abstract
Magnetic fields can have profound effects on the motion of electrons in quantum materials. Two-dimensional electron systems subject to strong magnetic fields are expected to exhibit quantized Hall conductivity, chiral edge currents and distinctive collective modes referred to as magnetoplasmons and magnetoexcitons. Generating these propagating collective modes in charge-neutral samples and imaging them at their native nanometre length scales have thus far been experimentally elusive. Here we visualize propagating magnetoexciton polaritons at their native length scales and report their magnetic-field-tunable dispersion in near-charge-neutral graphene. Imaging these collective modes and their associated nano-electro-optical responses allows us to identify polariton-modulated optical and photo-thermal electric effects at the sample edges, which are the most pronounced near charge neutrality. Our work is enabled by innovations in cryogenic near-field optical microscopy techniques that allow for the nano-imaging of the near-field responses of two-dimensional materials under magnetic fields up to 7 T. This nano-magneto-optics approach allows us to explore and manipulate magnetopolaritons in specimens with low carrier doping via harnessing high magnetic fields.
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Affiliation(s)
- Michael Dapolito
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Makoto Tsuneto
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Wenjun Zheng
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Lukas Wehmeier
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Suheng Xu
- Department of Physics, Columbia University, New York, NY, USA
| | - Xinzhong Chen
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Jiacheng Sun
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Zengyi Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Yinming Shao
- Department of Physics, Columbia University, New York, NY, USA
| | - Ran Jing
- Department of Physics, Columbia University, New York, NY, USA
| | - Shuai Zhang
- Department of Physics, Columbia University, New York, NY, USA
| | - Adrien Bercher
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Yinan Dong
- Department of Physics, Columbia University, New York, NY, USA
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, NY, USA
| | - Vibhu Ravindran
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Zijian Zhou
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Mila Petrovic
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Adrian Gozar
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - G L Carr
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Qiang Li
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Alexey B Kuzmenko
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Michael M Fogler
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA.
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
| | - Mengkun Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
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4
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Dapolito M, Tsuneto M, Zheng W, Wehmeier L, Xu S, Chen X, Sun J, Du Z, Shao Y, Jing R, Zhang S, Bercher A, Dong Y, Halbertal D, Ravindran V, Zhou Z, Petrovic M, Gozar A, Carr GL, Li Q, Kuzmenko AB, Fogler MM, Basov DN, Du X, Liu M. Author Correction: Infrared nano-imaging of Dirac magnetoexcitons in graphene. Nat Nanotechnol 2023; 18:1516. [PMID: 37978329 DOI: 10.1038/s41565-023-01569-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Affiliation(s)
- Michael Dapolito
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Makoto Tsuneto
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Wenjun Zheng
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Lukas Wehmeier
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Suheng Xu
- Department of Physics, Columbia University, New York, NY, USA
| | - Xinzhong Chen
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Jiacheng Sun
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Zengyi Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Yinming Shao
- Department of Physics, Columbia University, New York, NY, USA
| | - Ran Jing
- Department of Physics, Columbia University, New York, NY, USA
| | - Shuai Zhang
- Department of Physics, Columbia University, New York, NY, USA
| | - Adrien Bercher
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Yinan Dong
- Department of Physics, Columbia University, New York, NY, USA
| | - Dorri Halbertal
- Department of Physics, Columbia University, New York, NY, USA
| | - Vibhu Ravindran
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Zijian Zhou
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Mila Petrovic
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Adrian Gozar
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - G L Carr
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - Qiang Li
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
- Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY, USA
| | - Alexey B Kuzmenko
- Département de Physique de la Matière Quantique, Université de Genève, Genève 4, Switzerland
| | - Michael M Fogler
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - D N Basov
- Department of Physics, Columbia University, New York, NY, USA.
| | - Xu Du
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
| | - Mengkun Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA.
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
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5
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Feres FH, Barcelos ID, Cadore AR, Wehmeier L, Nörenberg T, Mayer RA, Freitas RO, Eng LM, Kehr SC, Maia FCB. Graphene Nano-Optics in the Terahertz Gap. Nano Lett 2023; 23:3913-3920. [PMID: 37126430 DOI: 10.1021/acs.nanolett.3c00578] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Graphene nano-optics at terahertz (THz) frequencies (ν) is theoretically anticipated to feature extraordinary effects. However, interrogating such phenomena is nontrivial, since the atomically thin graphene dimensionally mismatches the THz radiation wavelength reaching hundreds of micrometers. Greater challenges happen in the THz gap (0.1-10 THz) wherein light sources are scarce. To surpass these barriers, we use a nanoscope illuminated by a highly brilliant and tunable free-electron laser to image the graphene nano-optical response from 1.5 to 6.0 THz. For ν < 2 THz, we observe a metal-like behavior of graphene, which screens optical fields akin to noble metals, since this excitation range approaches its charge relaxation frequency. At 3.8 THz, plasmonic resonances cause a field-enhancement effect (FEE) that improves the graphene imaging power. Moreover, we show that the metallic behavior and the FEE are tunable upon electrical doping, thus providing further control of these graphene nano-optical properties in the THz gap.
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Affiliation(s)
- Flávio H Feres
- "Gleb Wataghin" Institute of Physics, State University of Campinas (UNICAMP), Campinas, Sao Paulo 13083-859, Brazil
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
| | - Ingrid D Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
| | - Alisson R Cadore
- Brazilian Nanotechnology National Laboratory LNNano, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
| | - Lukas Wehmeier
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States of America
| | - Tobias Nörenberg
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- Würzburg-Dresden Cluster of Excellence - EXC 2147 (ct.qmat), Technische Universität Dresden, 01062 Dresden, Germany
| | - Rafael A Mayer
- "Gleb Wataghin" Institute of Physics, State University of Campinas (UNICAMP), Campinas, Sao Paulo 13083-859, Brazil
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
| | - Raul O Freitas
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
| | - Lukas M Eng
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- Würzburg-Dresden Cluster of Excellence - EXC 2147 (ct.qmat), Technische Universität Dresden, 01062 Dresden, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- Würzburg-Dresden Cluster of Excellence - EXC 2147 (ct.qmat), Technische Universität Dresden, 01062 Dresden, Germany
| | - Francisco C B Maia
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Sao Paulo 13083-970, Brazil
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6
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Barnett J, Wehmeier L, Heßler A, Lewin M, Pries J, Wuttig M, Klopf JM, Kehr SC, Eng LM, Taubner T. Far-Infrared Near-Field Optical Imaging and Kelvin Probe Force Microscopy of Laser-Crystallized and -Amorphized Phase Change Material Ge 3Sb 2Te 6. Nano Lett 2021; 21:9012-9020. [PMID: 34665620 DOI: 10.1021/acs.nanolett.1c02353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chalcogenide phase change materials reversibly switch between non-volatile states with vastly different optical properties, enabling novel active nanophotonic devices. However, a fundamental understanding of their laser-switching behavior is lacking and the resulting local optical properties are unclear at the nanoscale. Here, we combine infrared scattering-type scanning near-field optical microscopy (SNOM) and Kelvin probe force microscopy (KPFM) to investigate four states of laser-switched Ge3Sb2Te6 (as-deposited amorphous, crystallized, reamorphized, and recrystallized) with nanometer lateral resolution. We find SNOM to be especially sensitive to differences between crystalline and amorphous states, while KPFM has higher sensitivity to changes introduced by melt-quenching. Using illumination from a free-electron laser, we use the higher sensitivity to free charge carriers of far-infrared (THz) SNOM compared to mid-infrared SNOM and find evidence that the local conductivity of crystalline states depends on the switching process. This insight into the local switching of optical properties is essential for developing active nanophotonic devices.
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Affiliation(s)
- Julian Barnett
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Lukas Wehmeier
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, 01062 Dresden, Germany
| | - Andreas Heßler
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Martin Lewin
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Julian Pries
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - Matthias Wuttig
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
| | - Lukas M Eng
- Institute of Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, 01062 Dresden, Germany
| | - Thomas Taubner
- I. Institute of Physics (IA), RWTH Aachen, 52074 Aachen, Germany
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Yao Z, Chen X, Wehmeier L, Xu S, Shao Y, Zeng Z, Liu F, Mcleod AS, Gilbert Corder SN, Tsuneto M, Shi W, Wang Z, Zheng W, Bechtel HA, Carr GL, Martin MC, Zettl A, Basov DN, Chen X, Eng LM, Kehr SC, Liu M. Probing subwavelength in-plane anisotropy with antenna-assisted infrared nano-spectroscopy. Nat Commun 2021; 12:2649. [PMID: 33976184 PMCID: PMC8113487 DOI: 10.1038/s41467-021-22844-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 03/29/2021] [Indexed: 02/03/2023] Open
Abstract
Infrared nano-spectroscopy based on scattering-type scanning near-field optical microscopy (s-SNOM) is commonly employed to probe the vibrational fingerprints of materials at the nanometer length scale. However, due to the elongated and axisymmetric tip shank, s-SNOM is less sensitive to the in-plane sample anisotropy in general. In this article, we report an easy-to-implement method to probe the in-plane dielectric responses of materials with the assistance of a metallic disk micro-antenna. As a proof-of-concept demonstration, we investigate here the in-plane phonon responses of two prototypical samples, i.e. in (100) sapphire and x-cut lithium niobate (LiNbO3). In particular, the sapphire in-plane vibrations between 350 cm-1 to 800 cm-1 that correspond to LO phonon modes along the crystal b- and c-axis are determined with a spatial resolution of < λ/10, without needing any fitting parameters. In LiNbO3, we identify the in-plane orientation of its optical axis via the phonon modes, demonstrating that our method can be applied without prior knowledge of the crystal orientation. Our method can be elegantly adapted to retrieve the in-plane anisotropic response of a broad range of materials, i.e. subwavelength microcrystals, van-der-Waals materials, or topological insulators.
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Affiliation(s)
- Ziheng Yao
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Xinzhong Chen
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Lukas Wehmeier
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany ,grid.4488.00000 0001 2111 7257ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Suheng Xu
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Yinming Shao
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Zimeng Zeng
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Fanwei Liu
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Alexander S. Mcleod
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Stephanie N. Gilbert Corder
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Makoto Tsuneto
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Wu Shi
- grid.184769.50000 0001 2231 4551Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA ,grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA ,grid.8547.e0000 0001 0125 2443Institute of Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, China
| | - Zihang Wang
- grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA
| | - Wenjun Zheng
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA
| | - Hans A. Bechtel
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - G. L. Carr
- grid.202665.50000 0001 2188 4229National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY USA
| | - Michael C. Martin
- grid.184769.50000 0001 2231 4551Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Alex Zettl
- grid.184769.50000 0001 2231 4551Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA ,grid.47840.3f0000 0001 2181 7878Department of Physics, University of California, Berkeley, CA USA
| | - D. N. Basov
- grid.21729.3f0000000419368729Department of Physics, Columbia University, New York, NY USA
| | - Xi Chen
- grid.12527.330000 0001 0662 3178State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Lukas M. Eng
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany ,grid.4488.00000 0001 2111 7257ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Susanne C. Kehr
- grid.4488.00000 0001 2111 7257Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
| | - Mengkun Liu
- grid.36425.360000 0001 2216 9681Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY USA ,grid.202665.50000 0001 2188 4229National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY USA
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9
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Feres FH, Mayer RA, Wehmeier L, Maia FCB, Viana ER, Malachias A, Bechtel HA, Klopf JM, Eng LM, Kehr SC, González JC, Freitas RO, Barcelos ID. Sub-diffractional cavity modes of terahertz hyperbolic phonon polaritons in tin oxide. Nat Commun 2021; 12:1995. [PMID: 33790286 PMCID: PMC8012705 DOI: 10.1038/s41467-021-22209-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 02/18/2021] [Indexed: 02/01/2023] Open
Abstract
Hyperbolic phonon polaritons have recently attracted considerable attention in nanophotonics mostly due to their intrinsic strong electromagnetic field confinement, ultraslow polariton group velocities, and long lifetimes. Here we introduce tin oxide (SnO2) nanobelts as a photonic platform for the transport of surface and volume phonon polaritons in the mid- to far-infrared frequency range. This report brings a comprehensive description of the polaritonic properties of SnO2 as a nanometer-sized dielectric and also as an engineered material in the form of a waveguide. By combining accelerator-based IR-THz sources (synchrotron and free-electron laser) with s-SNOM, we employed nanoscale far-infrared hyper-spectral-imaging to uncover a Fabry-Perot cavity mechanism in SnO2 nanobelts via direct detection of phonon-polariton standing waves. Our experimental findings are accurately supported by notable convergence between theory and numerical simulations. Thus, the SnO2 is confirmed as a natural hyperbolic material with unique photonic properties essential for future applications involving subdiffractional light traffic and detection in the far-infrared range.
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Affiliation(s)
- Flávio H Feres
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
- Physics Department, Gleb Wataghin Physics Institute, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Rafael A Mayer
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
- Physics Department, Gleb Wataghin Physics Institute, University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Lukas Wehmeier
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Francisco C B Maia
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil
| | - E R Viana
- Department of Physics, Universidade Tecnológica Federal do Paraná (UTFPR), Curitiba, PR, Brazil
| | - Angelo Malachias
- Department of Physics, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Hans A Bechtel
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Lukas M Eng
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
- ct.qmat, Dresden-Würzburg Cluster of Excellence-EXC 2147, Technische Universität Dresden, Dresden, Germany
| | - Susanne C Kehr
- Institute of Applied Physics, Technische Universität Dresden, Dresden, Germany
| | - J C González
- Department of Physics, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Raul O Freitas
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
| | - Ingrid D Barcelos
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
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10
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de Oliveira TVAG, Nörenberg T, Álvarez-Pérez G, Wehmeier L, Taboada-Gutiérrez J, Obst M, Hempel F, Lee EJH, Klopf JM, Errea I, Nikitin AY, Kehr SC, Alonso-González P, Eng LM. Nanoscale-Confined Terahertz Polaritons in a van der Waals Crystal. Adv Mater 2021; 33:e2005777. [PMID: 33270287 DOI: 10.1002/adma.202005777] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/16/2020] [Indexed: 05/28/2023]
Abstract
Electromagnetic field confinement is crucial for nanophotonic technologies, since it allows for enhancing light-matter interactions, thus enabling light manipulation in deep sub-wavelength scales. In the terahertz (THz) spectral range, radiation confinement is conventionally achieved with specially designed metallic structures-such as antennas or nanoslits-with large footprints due to the rather long wavelengths of THz radiation. In this context, phonon polaritons-light coupled to lattice vibrations-in van der Waals (vdW) crystals have emerged as a promising solution for controlling light beyond the diffraction limit, as they feature extreme field confinements and low optical losses. However, experimental demonstration of nanoscale-confined phonon polaritons at THz frequencies has so far remained elusive. Here, it is provided by employing scattering-type scanning near-field optical microscopy combined with a free-electron laser to reveal a range of low-loss polaritonic excitations at frequencies from 8 to 12 THz in the vdW semiconductor α-MoO3 . In this study, THz polaritons are visualized with: i) in-plane hyperbolic dispersion, ii) extreme nanoscale field confinement (below λo ⁄75), and iii) long polariton lifetimes, with a lower limit of >2 ps.
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Affiliation(s)
- Thales V A G de Oliveira
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, 0 1328, Germany
| | - Tobias Nörenberg
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
| | - Gonzalo Álvarez-Pérez
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Lukas Wehmeier
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Javier Taboada-Gutiérrez
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Maximilian Obst
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Franz Hempel
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Eduardo J H Lee
- Departamento de Física de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, 28 049, Spain
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, 0 1328, Germany
| | - Ion Errea
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, 20 018, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, 20 018, Spain
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20 018, Spain
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20 018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Susanne C Kehr
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Pablo Alonso-González
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Lukas M Eng
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
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11
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Döring J, Lang D, Wehmeier L, Kuschewski F, Nörenberg T, Kehr SC, Eng LM. Low-temperature nanospectroscopy of the structural ferroelectric phases in single-crystalline barium titanate. Nanoscale 2018; 10:18074-18079. [PMID: 30230501 DOI: 10.1039/c8nr04081h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We optically investigate the local-scale ferroelectric domain structure of tetragonal, orthorhombic, and rhombohedral barium titanate (BTO) single crystals using scattering-type scanning near-field infrared (IR) optical microscopy (s-SNIM) at temperatures down to 150 K. Thanks to the precisely tunable narrow-band free-electron laser FELBE, we are able to explore the spectral fingerprints and IR resonances of these three phases and their domain orientations in the optical IR near-field. More clearly, every structural phase is analyzed with respect to its near-field resonances close to a wavelength of 17 μm when exploring the (111)-oriented BTO sample surface. Furthermore, near-field imaging at these resonances is performed, that clearly allows for the unambiguous optical identification of different domain orientations. Since our s-SNIM is based on a non-contact scanning force microscope, our s-SNIM findings are backed up by sample-topography and piezoresponse force microscopy (PFM) imaging, providing complementary information in an excellent match to the s-SNIM results.
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Affiliation(s)
- Jonathan Döring
- Institut für Angewandte Physik, Technische Universität Dresden, Nöthnitzer Str. 61, D-01187 Dresden, Germany.
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Tauch A, Wehmeier L, Götker S, Pühler A, Kalinowski J. Relaxed rrn expression and amino acid requirement of a Corynebacterium glutamicum rel mutant defective in (p)ppGpp metabolism. FEMS Microbiol Lett 2001; 201:53-8. [PMID: 11445167 DOI: 10.1111/j.1574-6968.2001.tb10732.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The stringent response in Corynebacterium glutamicum was investigated. Sets of rrn-cat fusions were constructed in their native chromosomal position to examine the effects of amino acid starvation in a rel(+) strain and a Deltarel mutant defective in (p)ppGpp metabolism. The expression of the six rrn operons in the rel(+) control was stringently regulated and reduced to 79% upon induction of amino acid starvation. The Deltarel mutant displayed a relaxed regulation and was unable to reduce the rrn expression under amino acid depletion conditions. In addition, the Deltarel mutant grew more slowly in minimal medium than a rel(+) control. This growth effect was restored by a plasmid-encoded copy of rel or, alternatively, by supplementation of the minimal medium with the amino acid mixture casamino acids. In particular, the Deltarel strain of C. glutamicum displayed a requirement for the amino acids histidine and serine.
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Affiliation(s)
- A Tauch
- Department of Genetics, University of Bielefeld, P.O. Box 100131, D-33501 Bielefeld, Germany
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13
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Tauch A, Kirchner O, Wehmeier L, Kalinowski J, Pühler A. Corynebacterium glutamicum DNA is subjected to methylation-restriction in Escherichia coli. FEMS Microbiol Lett 1994; 123:343-7. [PMID: 7988915 DOI: 10.1111/j.1574-6968.1994.tb07246.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Efficient electroporation of Escherichia coli with plasmid DNA isolated from Corynebacterium glutamicum depends on the use of Mcr-deficient E. coli strains. The transformation frequency increased nearly 800-fold when the Mcr-deficient E. coli DH5 alpha MCR was used instead of E. coli DH5 alpha. We used E. coli strains with different mutations in the methyl-specific restriction systems to show that McrBC-deficiency is sufficient to generate this effect. The results imply that C. glutamicum DNA contains methylcytosine in specific sequences recognized by the E. coli McrBC system.
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Affiliation(s)
- A Tauch
- Department of Genetics, University of Bielefeld, Germany
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