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Macis S, D'Arco A, Mosesso L, Paolozzi MC, Tofani S, Tomarchio L, Tummala PP, Ghomi S, Stopponi V, Bonaventura E, Massetti C, Codegoni D, Serafini A, Targa P, Zacchigna M, Lamperti A, Martella C, Molle A, Lupi S. Terahertz and Infrared Plasmon Polaritons in PtTe 2 Type-II Dirac Topological Semimetal. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2400554. [PMID: 38733453 DOI: 10.1002/adma.202400554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/18/2024] [Indexed: 05/13/2024]
Abstract
Surface plasmon polaritons (SPPs) are electromagnetic excitations existing at the interface between a metal and a dielectric. SPPs provide a promising path in nanophotonic devices for light manipulation at the micro and nanoscale with applications in optoelectronics, biomedicine, and energy harvesting. Recently, SPPs are extended to unconventional materials like graphene, transparent oxides, superconductors, and topological systems characterized by linearly dispersive electronic bands. In this respect, 3D Dirac and Weyl semimetals offer a promising frontier for infrared (IR) and terahertz (THz) radiation tuning by topologically-protected SPPs. In this work, the THz-IR optical response of platinum ditelluride (PtTe2) type-II Dirac topological semimetal films grown on Si substrates is investigated. SPPs generated on microscale ribbon arrays of PtTe2 are detected in the far-field limit, finding an excellent agreement among measurements, theoretical models, and electromagnetic simulation data. The far-field measurements are further supported by near-field IR data which indicate a strong electric field enhancement due to the SPP excitation near the ribbon edges. The present findings indicate that the PtTe2 ribbon array appears an ideal active layout for geometrically tunable SPPs thus inspiring a new fashion of optically tunable materials in the technologically demanding THz and IR spectrum.
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Affiliation(s)
- Salvatore Macis
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Annalisa D'Arco
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Lorenzo Mosesso
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Maria Chiara Paolozzi
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Silvia Tofani
- CNR-IMM, Unit of Rome, Via del Fosso del Cavaliere 100, Rome, 00133, Italy
| | - Luca Tomarchio
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | | | - Sara Ghomi
- CNR-IMM, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
| | - Veronica Stopponi
- CNR-IOM, Area Science Park Strada Statale 14, km 163,5, Basovizza, TS, 34149, Italy
| | - Eleonora Bonaventura
- CNR-IMM, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
- Department of Materials Science, University of Milano-Bicocca, Via Cozzi, 55, Milan, 20125, Italy
| | - Chiara Massetti
- CNR-IMM, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
| | - Davide Codegoni
- STMicroelectronics, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
| | - Andrea Serafini
- STMicroelectronics, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
| | - Paolo Targa
- STMicroelectronics, via C. Olivetti 2, Agrate Brianza (MB), I-20864, Italy
| | - Michele Zacchigna
- CNR-IOM, Area Science Park Strada Statale 14, km 163,5, Basovizza, TS, 34149, Italy
| | | | | | | | - Stefano Lupi
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Rome, 00185, Italy
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2
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Pistore V, Viti L, Schiattarella C, Wang Z, Law S, Mitrofanov O, Vitiello MS. Holographic Nano-Imaging of Terahertz Dirac Plasmon Polaritons in Topological Insulator Antenna Resonators. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308116. [PMID: 38152928 DOI: 10.1002/smll.202308116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/17/2023] [Indexed: 12/29/2023]
Abstract
Excitation of Dirac plasmon polaritons (DPPs) in bi-dimensional materials have attracted considerable interest in recent years, both from perspectives of understanding their physics and exploring their transformative potential for nanophotonic devices, including ultra-sensitive plasmonic sensors, ultrafast saturable absorbers, modulators, and switches. Topological insulators (TIs) represent an ideal technological platform in this respect because they can support plasmon polaritons formed by Dirac carriers in the topological surface states. Tracing propagation of DPPs is a very challenging task, particularly at terahertz (THz) frequencies, where the DPP wavelength becomes over one order of magnitude shorter than the free space photon wavelength. Furthermore, severe attenuation hinders the comprehensive analysis of their characteristics. Here, the properties of DPPs in real TI-based devices are revealed. Bi2Se3 rectangular antennas can efficiently confine the propagation of DPPs to a single dimension and, as a result, enhance the DPPs visibility despite the strong intrinsic attenuation. The plasmon dispersion and loss properties from plasmon profiles are experimentally determined, along the antennas, obtained using holographic near-field nano-imaging in a wide range of THz frequencies, from 2.05 to 4.3 THz. The detailed investigation of the unveiled DPP properties can guide the design of novel topological quantum devices exploiting their directional propagation.
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Affiliation(s)
- Valentino Pistore
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
| | - Leonardo Viti
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
| | - Chiara Schiattarella
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
| | - Zhengtianye Wang
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Stephanie Law
- Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Oleg Mitrofanov
- University College London, Electronic and Electrical Engineering, London, WC1E 7JE, UK
| | - Miriam S Vitiello
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
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3
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Li YW, Chen MN, Dai JY, Zhou Y. Guiding infrared electromagnetic waves through TI nanowires with extremely large wavenumber and azimuthal index. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:275001. [PMID: 38537285 DOI: 10.1088/1361-648x/ad3876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
In this paper, the dispersion relations of the surface plasmon polaritons (SPPs) in TI nanowires have been investigated. For simplicity, TI nanowire has been modeled as a dielectric cylinder with a conductive surface, the conductivity of which is an anti-symmetric tensor. The off-diagonal terms of the conductivity tensor only slightly change the dispersion relations. Due to small conductivities, these SPPs have extremely large wavenumbers and azimuthal indices; the electric fields are tightly confined near the conductive surface. For high-order modes, cut-off phenomena have been observed. In the end, the effects of losses and much larger bulk permittivities on the dispersion relations of surface plasmons have been discussed. The simple model proposed in this paper can be directly applied to other materials with arbitrary surface conductivity. Our investigations show that TI nanostructures are promising platforms for nanophotonic applications in the future.
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Affiliation(s)
- Y W Li
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - M N Chen
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - J Y Dai
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - Yu Zhou
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
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4
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Thanopulos I, Yannopapas V, Paspalakis E. Strong Coupling Dynamics of a Quantum Emitter near a Topological Insulator Nanoparticle. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2787. [PMID: 37887938 PMCID: PMC10609747 DOI: 10.3390/nano13202787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/11/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
We study the spontaneous emission dynamics of a quantum emitter near a topological insulator Bi2Se3 spherical nanoparticle. Using the electromagnetic Green's tensor method, we find exceptional Purcell factors of the quantum emitter up to 1010 at distances between the emitter and the nanoparticle as large as half the nanoparticle's radius in the terahertz regime. We study the spontaneous emission evolution of a quantum emitter for various transition frequencies in the terahertz and various vacuum decay rates. For short vacuum decay times, we observe non-Markovian spontaneous emission dynamics, which correspond perfectly to values of well-established measures of non-Markovianity and possibly indicate considerable dynamical quantum speedup. The dynamics turn progressively Markovian as the vacuum decay times increase, while in this regime, the non-Markovianity measures are nullified, and the quantum speedup vanishes. For the shortest vacuum decay times, we find that the population remains trapped in the emitter, which indicates that a hybrid bound state between the quantum emitter and the continuum of electromagnetic modes as affected by the nanoparticle has been formed. This work demonstrates that a Bi2Se3 spherical nanoparticle can be a nanoscale platform for strong light-matter coupling.
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Affiliation(s)
- Ioannis Thanopulos
- Materials Science Department, School of Natural Sciences, University of Patras, 265 04 Patras, Greece;
| | - Vassilios Yannopapas
- Department of Physics, National Technical University of Athens, 157 80 Athens, Greece;
| | - Emmanuel Paspalakis
- Materials Science Department, School of Natural Sciences, University of Patras, 265 04 Patras, Greece;
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5
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Krishnamoorthy HNS, Dubrovkin AM, Adamo G, Soci C. Topological Insulator Metamaterials. Chem Rev 2023; 123:4416-4442. [PMID: 36943013 DOI: 10.1021/acs.chemrev.2c00594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Confinement of electromagnetic fields at the subwavelength scale via metamaterial paradigms is an established method to engineer light-matter interaction in most common material systems, from insulators to semiconductors and from metals to superconductors. In recent years, this approach has been extended to the realm of topological materials, providing a new avenue to access nontrivial features of their electronic band structure. In this review, we survey various topological material classes from a photonics standpoint, including crystal growth and lithographic structuring methods. We discuss how exotic electronic features such as spin-selective Dirac plasmon polaritons in topological insulators or hyperbolic plasmon polaritons in Weyl semimetals may give rise to unconventional magneto-optic, nonlinear, and circular photogalvanic effects in metamaterials across the visible to infrared spectrum. Finally, we dwell on how these effects may be dynamically controlled by applying external perturbations in the form of electric and magnetic fields or ultrafast optical pulses. Through these examples and future perspectives, we argue that topological insulator, semimetal and superconductor metamaterials are unique systems to bridge the missing links between nanophotonic, electronic, and spintronic technologies.
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Affiliation(s)
- Harish N S Krishnamoorthy
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Alexander M Dubrovkin
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Giorgio Adamo
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Cesare Soci
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Centre for Disruptive Photonic Technologies, The Photonic Institute, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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6
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Caballero-Calero O, Ruiz-Clavijo A, Manzano CV, Martín-González M, Armelles G. Plasmon Resonances in 1D Nanowire Arrays and 3D Nanowire Networks of Topological Insulators and Metals. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:154. [PMID: 36616063 PMCID: PMC9823705 DOI: 10.3390/nano13010154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/19/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
The 1D nanowire arrays and 3D nanowire networks of topological insulators and metals have been fabricated by template-assisted deposition of Bi2Te3 and Ni inside anodic aluminum oxide (AAO) templates, respectively. Despite the different origins of the plasmon capabilities of the two materials, the results indicate that the optical response is determined by plasmon resonances, whose position depends on the nanowire interactions and material properties. Due to the thermoelectric properties of Bi2Te3 nanowires, these plasmon resonances could be used to develop new ways of enhancing thermal gradients and their associated thermoelectric power.
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7
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Zhou Y, Chen MN. Surface plasmons in anisotropic 3D gapped topological insulators. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 35:085001. [PMID: 36541525 DOI: 10.1088/1361-648x/aca7aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Topological insulators (TIs) are materials having conductive surfaces but insulating bulk, which are ideal platforms for plasmonic applications. The most commonly known TIs, such as Bi2Se3and Bi2Te3, are in fact highly anisotropic. The dielectric constants are largely different parallel and perpendicular to the surface. Here, we have extended the electromagnetic calculations of the surface plasmons in TIs to the anisotropic case. Magnetic field perpendicular to the surface is allowed, which opens a gap among the surface states. We model anisotropic TIs as bulk dielectric materials with different in-plane and out-of-plane permittivities; the surface states caused by the band inversion lead to a two-dimensional conductivity which supports surface plasmons. We have found two rather than one surface modes. Due to such anisotropy, quasi transverse electric (TE) polarized mode may occur near the interband transition threshold. Far below the transition frequency, another mode with both TE and transverse magnetic polarized components dominates, the dispersion relation of which is seriously modified by the Hall conductivity. By taking Bi2Te3as an example, we have derived the conductivity tensor with the consideration of the hexagonal warping effect, and solved the above mentioned two surface plasmon modes. In the end, finite element method has been used to calculate the electric field distributions. Our extension of the electromagnetic calculations of surface plasmons including a specific kind of anisotropy might be useful in other surface conductive materials with similar symmetry as well.
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Affiliation(s)
- Yu Zhou
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - M N Chen
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
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8
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In C, Kim UJ, Choi H. Two-dimensional Dirac plasmon-polaritons in graphene, 3D topological insulator and hybrid systems. LIGHT, SCIENCE & APPLICATIONS 2022; 11:313. [PMID: 36302746 PMCID: PMC9613982 DOI: 10.1038/s41377-022-01012-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/22/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Collective oscillations of massless particles in two-dimensional (2D) Dirac materials offer an innovative route toward implementing atomically thin devices based on low-energy quasiparticle interactions. Strong confinement of near-field distribution on the 2D surface is essential to demonstrate extraordinary optoelectronic functions, providing means to shape the spectral response at the mid-infrared (IR) wavelength. Although the dynamic polarization from the linear response theory has successfully accounted for a range of experimental observations, a unified perspective was still elusive, connecting the state-of-the-art developments based on the 2D Dirac plasmon-polaritons. Here, we review recent works on graphene and three-dimensional (3D) topological insulator (TI) plasmon-polariton, where the mid-IR and terahertz (THz) radiation experiences prominent confinement into a deep-subwavelength scale in a novel optoelectronic structure. After presenting general light-matter interactions between 2D Dirac plasmon and subwavelength quasiparticle excitations, we introduce various experimental techniques to couple the plasmon-polaritons with electromagnetic radiations. Electrical and optical controls over the plasmonic excitations reveal the hybridized plasmon modes in graphene and 3D TI, demonstrating an intense near-field interaction of 2D Dirac plasmon within the highly-compressed volume. These findings can further be applied to invent optoelectronic bio-molecular sensors, atomically thin photodetectors, and laser-driven light sources.
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Affiliation(s)
- Chihun In
- Department of Physics, Freie Universität Berlin, Berlin, 14195, Germany
- Department of Physical Chemistry, Fritz-Haber-Institute of the Max-Planck-Society, Berlin, 14195, Germany
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Un Jeong Kim
- Advanced Sensor Laboratory, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do, 16419, Republic of Korea.
| | - Hyunyong Choi
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
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9
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Thanopulos I, Yannopapas V, Paspalakis E. Topological insulator nanoparticles for strong light-matter interaction in the terahertz regime. OPTICS LETTERS 2022; 47:5240-5243. [PMID: 36181231 DOI: 10.1364/ol.473317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/10/2022] [Indexed: 06/16/2023]
Abstract
We study the spontaneous emission (SPEM) for a quantum emitter (QUEM) near a topological insulator Bi2Se3 nanosphere. We calculate numerically the QUEM Purcell factor near nanospheres of radii between 40 nm and 100 nm, with and without taking into account the topologically protected delocalized states at the surface of the nanosphere. We find exceptionally large Purcell factors up to 1010 at distances between the QUEM and the nanosphere as large as half its radius in the terahertz regime. By computing the SPEM dynamics for a QUEM with transition frequencies in the terahertz and free-space decay rates in the nanosecond to millisecond range, we observe intense reversible dynamics, as well as population trapping effects. This work demonstrates that a Bi2Se3 nanosphere provides the conditions for strong light-matter interaction at the nanoscale in the terahertz regime.
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10
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Liu Y, Acuna W, Zhang H, Ho DQ, Hu R, Wang Z, Janotti A, Bryant G, Davydov AV, Zide JMO, Law S. Bi 2Se 3 Growth on (001) GaAs Substrates for Terahertz Integrated Systems. ACS APPLIED MATERIALS & INTERFACES 2022; 14:42683-42691. [PMID: 36074957 DOI: 10.1021/acsami.2c11135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Terahertz (THz) technologies have been of interest for many years due to the variety of applications including gas sensing, nonionizing imaging of biological systems, security and defense, and so forth. To date, scientists have used different classes of materials to perform different THz functions. However, to assemble an on-chip THz integrated system, we must understand how to integrate these different materials. Here, we explore the growth of Bi2Se3, a topological insulator material that could serve as a plasmonic waveguide in THz integrated devices, on technologically important GaAs(001) substrates. We explore surface treatments and find that an atomically smooth GaAs surface is critical to achieving high-quality Bi2Se3 films despite the relatively weak film/substrate interaction. Calculations indicate that the Bi2Se3/GaAs interface is likely selenium-terminated and shows no evidence of chemical bonding between the Bi2Se3 and the substrate. These results are a guide for integrating van der Waals materials with conventional semiconductor substrates and serve as the first steps toward achieving an on-chip THz integrated system.
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Affiliation(s)
- Yongchen Liu
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Wilder Acuna
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Huairuo Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Theiss Research, Inc., La Jolla, California 92037, United States
| | - Dai Q Ho
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Ruiqi Hu
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Zhengtianye Wang
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Anderson Janotti
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Garnett Bryant
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Joshua M O Zide
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Stephanie Law
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
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11
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Glinka YD, He T, Sun XW. Two-photon IR pumped UV-Vis transient absorption spectroscopy of Dirac fermions in the topological insulator Bi 2Se 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:465301. [PMID: 36075223 DOI: 10.1088/1361-648x/ac90a7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
It is often taken for granted that in pump-probe experiments on the topological insulator (TI) Bi2Se3using IR pumping with a commercial Ti:sapphire laser [∼800 nm (1.55 eV photon energy)], the electrons are excited in the one-photon absorption regime, even when pumped with absorbed fluences in the mJ cm-2range. Here, using UV-Vis transient absorption (TA) spectroscopy, we show that even at low-power Infrared (IR) pumping with absorbed fluences in theμJ cm-2range, the TA spectra of the TI Bi2Se3extend across a part of the UV and the entire visible region. This observation suggests unambiguously that the two-photon pumping regime accompanies the usual one-photon pumping regime even at low laser powers applied. We attribute the high efficiency of two-photon pumping to the giant nonlinearity of Dirac fermions in the Dirac surface states (SS). On the contrary, one-photon pumping is associated with the excitation of bound valence electrons in the bulk into the conduction band. Two mechanisms of absorption bleaching were also revealed since they manifest themselves in different spectral regions of probing and cause the appearance of three different relaxation dynamics. These two mechanisms were attributed to the filling of the phase-space in the Dirac SS and bulk states, followed by the corresponding Pauli blocking.
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Affiliation(s)
- Yuri D Glinka
- Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting, Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Institute of Physics, National Academy of Sciences of Ukraine, Kyiv 03028, Ukraine
| | - Tingchao He
- College of Physics and Energy, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xiao Wei Sun
- Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting, Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Shenzhen Planck Innovation Technologies Pte Ltd, Longgang, Shenzhen 518112, People's Republic of China
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12
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Chen S, Bylinkin A, Wang Z, Schnell M, Chandan G, Li P, Nikitin AY, Law S, Hillenbrand R. Real-space nanoimaging of THz polaritons in the topological insulator Bi 2Se 3. Nat Commun 2022; 13:1374. [PMID: 35296642 PMCID: PMC8927118 DOI: 10.1038/s41467-022-28791-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 02/09/2022] [Indexed: 12/31/2022] Open
Abstract
Plasmon polaritons in topological insulators attract attention from a fundamental perspective and for potential THz photonic applications. Although polaritons have been observed by THz far-field spectroscopy on topological insulator microstructures, real-space imaging of propagating THz polaritons has been elusive so far. Here, we show spectroscopic THz near-field images of thin Bi2Se3 layers (prototypical topological insulators) revealing polaritons with up to 12 times increased momenta as compared to photons of the same energy and decay times of about 0.48 ps, yet short propagation lengths. From the images we determine and analyze the polariton dispersion, showing that the polaritons can be explained by the coupling of THz radiation to various combinations of Dirac and massive carriers at the Bi2Se3 surfaces, massive bulk carriers and optical phonons. Our work provides critical insights into the nature of THz polaritons in topological insulators and establishes instrumentation and methodology for imaging of THz polaritons.
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Affiliation(s)
- Shu Chen
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain
| | - Andrei Bylinkin
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain.,Donostia International Physics Center (DIPC), 20018, Donostia - San Sebastián, Spain
| | - Zhengtianye Wang
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Martin Schnell
- CIC nanoGUNE BRTA, 20018, Donostia - San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Greeshma Chandan
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Peining Li
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), 20018, Donostia - San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Stephanie Law
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, USA
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain. .,CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, 20018, Donostia-San Sebastián, Spain.
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Sugimoto H, Tabata H. Nonlabeled detection of specific intermolecular bondings by terahertz surface plasmon resonance of topological insulator. OPTICS LETTERS 2021; 46:3897-3900. [PMID: 34388769 DOI: 10.1364/ol.432403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
The terahertz (THz) band, which corresponds to intermolecular binding energy, is the key to achieving a nonlabeled biosensor. To realize high-sensitivity binding detection, we focused on surface plasmon resonance (SPR) in the THz range. Using THz-SPR enhanced a in topological insulator, we expect to observe the synergistic effects of two resonance phenomena, namely intermolecular vibrational resonance and SPR. In this Letter, we report the nonlabeled detection of biomolecular binding by the topological insulator THz-SPR. Bi2Se3 was processed in a microribbon array to enhance the SPR in the THz range. The avidin-biotin specific binding, which is similar to the antigen-antibody reaction mechanism and has powerful interactions, was observed owing to enhancement by Bi2Se3 THz-SPR. This work paves the way for a system to directly measure specific molecular bonds using topological insulators.
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Rider MS, Sokolikova M, Hanham SM, Navarro-Cía M, Haynes PD, Lee DKK, Daniele M, Cestelli Guidi M, Mattevi C, Lupi S, Giannini V. Experimental signature of a topological quantum dot. NANOSCALE 2020; 12:22817-22825. [PMID: 33174899 DOI: 10.1039/d0nr06523d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Topological insulator nanoparticles (TINPs) host topologically protected Dirac surface states, just like their bulk counterparts. For TINPs of radius <100 nm, quantum confinement on the surface results in the discretization of the Dirac cone. This system of discrete energy levels is referred to as a topological quantum dot (TQD) with energy level spacing on the order of Terahertz (THz), which is tunable with material-type and particle size. The presence of these discretized energy levels in turn leads to a new electron-mediated phonon-light coupling in the THz range, and the resulting mode can be observed in the absorption cross-section of the TINPs. We present the first experimental evidence of this new quantum phenomenon in Bi2Te3 topological quantum dots, remarkably observed at room temperature.
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Affiliation(s)
- Marie S Rider
- The Blackett Laboratory, Imperial College London, London SW7 2AZ, UK.
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