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Dong J, Inbar HS, Dempsey CP, Engel AN, Palmstrøm CJ. Strain Solitons in an Epitaxially Strained van der Waals-like Material. NANO LETTERS 2024; 24:4493-4497. [PMID: 38498733 PMCID: PMC11036392 DOI: 10.1021/acs.nanolett.4c00382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 03/20/2024]
Abstract
Strain solitons are quasi-dislocations that form in van der Waals materials to relieve the energy associated with lattice or rotational mismatch. Novel electronic properties of strain solitons were predicted and observed. To date, strain solitons have been observed only in exfoliated crystals or mechanically strained crystals. The lack of a scalable approach toward the generation of strain solitons poses a significant challenge in the study of and use of their properties. Here, we report the formation of strain solitons with epitaxial growth of bismuth on InSb(111)B by molecular beam epitaxy. The morphology of the strain solitons for films of varying thickness is characterized with scanning tunneling microscopy, and the local strain state is determined from atomic resolution images. Bending in the solitons is attributed to interactions with the interface, and large angle bending is associated with edge dislocations. Our results enable the scalable generation of strain solitons.
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Affiliation(s)
- Jason
T. Dong
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Hadass S. Inbar
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Connor P. Dempsey
- Deparment
of Electrical and Computer Engineering, University of California, Santa
Barbara, California 93106, United States
| | - Aaron N. Engel
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Christopher J. Palmstrøm
- Materials
Department, University of California, Santa Barbara, California 93106, United States
- Deparment
of Electrical and Computer Engineering, University of California, Santa
Barbara, California 93106, United States
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2
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Wan Y, Li J, Liu Q. Topological magnetoelectric response in ferromagnetic axion insulators. Natl Sci Rev 2024; 11:nwac138. [PMID: 38264342 PMCID: PMC10804227 DOI: 10.1093/nsr/nwac138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 01/25/2024] Open
Abstract
The topological magnetoelectric effect (TME) is a hallmark response of the topological field theory, which provides a paradigm shift in the study of emergent topological phenomena. However, its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface states. Here, we theoretically propose that axion insulators with a simple ferromagnetic configuration, such as the MnBi2Te4/(Bi2Te3)n family, provide an ideal playground to realize the TME. In the designed triangular prism geometry, all the surface states are magnetically gapped. Under a vertical electric field, the surface Hall currents give rise to a nearly half-quantized orbital moment, accompanied by a gapless chiral hinge mode circulating in parallel. Thus, the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric field. Our work paves the way for direct observation of the TME in realistic axion-insulator materials.
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Affiliation(s)
- Yuhao Wan
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiayu Li
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
| | - Qihang Liu
- Department of Physics and Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
- Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Mihalyuk AN, Bondarenko LV, Tupchaya AY, Gruznev DV, Solovova NY, Golyashov VA, Tereshchenko OE, Okuda T, Kimura A, Eremeev SV, Zotov AV, Saranin AA. Emergence of quasi-1D spin-polarized states in ultrathin Bi films on InAs(111)A for spintronics applications. NANOSCALE 2024; 16:1272-1281. [PMID: 38126765 DOI: 10.1039/d3nr03830k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The discovery, characterization, and control of heavy-fermion low-dimensional materials are central to nanoscience since quantum phenomena acquire an exotic and highly tunable character. In this work, through a variety of comprehensive experimental and theoretical techniques, it was observed and predicted that the synthesis of ultrathin Bi films on the InAs(111)A surface produces quasi-one-dimensional spin-polarized states, providing a platform for the realization of a unique spin-transport regime in the system. Scanning tunneling microscopy and low-energy electron diffraction measurements revealed that the InAs(111)A substrate facilitates the formation of the Bi-dimer phase of 2√3 × 3 periodicity with an admixture of the Bi-bilayer phase under submonolayer Bi deposition. X-ray photoelectron spectroscopy (XPS) measurements have shown the chemical stability of the Bi-induced phases, while spin and angle resolved photoemission spectroscopy (SARPES) observations combined with state-of-the-art DFT calculations have revealed that the electronic spectrum of the Bi-dimer phase holds a quasi-1D hole-like spin-split state at the Fermi level with advanced spin texture, whereas the Bi-bilayer phase demonstrates metallic states with large Rashba spin-splitting. The band structure of the Bi/InAs(111)A interface is discovered to hold great potential as a high-performance spintronics material fabricated in the ultimate two-dimensional limit.
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Affiliation(s)
- Alexey N Mihalyuk
- Institute of High Technologies and Advanced Materials, Far Eastern Federal University, 690950 Vladivostok, Russia.
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Leonid V Bondarenko
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Alexandra Y Tupchaya
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Dimitry V Gruznev
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | | | - Vladimir A Golyashov
- Novosibirsk State University, 630090 Novosibirsk, Russia
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Oleg E Tereshchenko
- Novosibirsk State University, 630090 Novosibirsk, Russia
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Taichi Okuda
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Akio Kimura
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Sergey V Eremeev
- Institute of Strength Physics and Materials Science, Tomsk 634055, Russia
| | - Andrey V Zotov
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
| | - Alexander A Saranin
- Institute of Automation and Control Processes FEB RAS, 690041 Vladivostok, Russia
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4
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Liu B, Wagner T, Enzner S, Eck P, Kamp M, Sangiovanni G, Claessen R. Moiré Pattern Formation in Epitaxial Growth on a Covalent Substrate: Sb on InSb(111)A. NANO LETTERS 2023; 23:3189-3195. [PMID: 37027539 DOI: 10.1021/acs.nanolett.2c04974] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Structural moiré superstructures arising from two competing lattices may lead to unexpected electronic behavior. Sb is predicted to show thickness-dependent topological properties, providing potential applications for low-energy-consuming electronic devices. Here we successfully synthesize ultrathin Sb films on semi-insulating InSb(111)A. Despite the covalent nature of the substrate, which has dangling bonds on the surface, we prove by scanning transmission electron microscopy that the first layer of Sb atoms grows in an unstrained manner. Rather than compensating for the lattice mismatch of -6.4% by structural modifications, the Sb films form a pronounced moiré pattern as we evidence by scanning tunneling microscopy. Our model calculations assign the moiré pattern to a periodic surface corrugation. In agreement with theoretical predictions, irrespective of the moiré modulation, the topological surface state known on a thick Sb film is experimentally confirmed to persist down to small film thicknesses, and the Dirac point shifts toward lower binding energies with a decrease in Sb thickness.
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Affiliation(s)
- Bing Liu
- Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - Tim Wagner
- Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - Stefan Enzner
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany
| | - Philipp Eck
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany
| | - Martin Kamp
- Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
| | - Giorgio Sangiovanni
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany
| | - Ralph Claessen
- Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
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5
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Liu Y, Benter S, Ong CS, Maciel RP, Björk L, Irish A, Eriksson O, Mikkelsen A, Timm R. A 2D Bismuth-Induced Honeycomb Surface Structure on GaAs(111). ACS NANO 2023; 17:5047-5058. [PMID: 36821844 PMCID: PMC10018767 DOI: 10.1021/acsnano.2c12863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) topological insulators have fascinating physical properties which are promising for applications within spintronics. In order to realize spintronic devices working at room temperature, materials with a large nontrivial gap are needed. Bismuthene, a 2D layer of Bi atoms in a honeycomb structure, has recently attracted strong attention because of its record-large nontrivial gap, which is due to the strong spin-orbit coupling of Bi and the unusually strong interaction of the Bi atoms with the surface atoms of the substrate underneath. It would be a significant step forward to be able to form 2D materials with properties such as bismuthene on semiconductors such as GaAs, which has a band gap size relevant for electronics and a direct band gap for optical applications. Here, we present the successful formation of a 2D Bi honeycomb structure on GaAs, which fulfills these conditions. Bi atoms have been incorporated into a clean GaAs(111) surface, with As termination, based on Bi deposition under optimized growth conditions. Low-temperature scanning tunneling microscopy and spectroscopy (LT-STM/S) demonstrates a well-ordered large-scale honeycomb structure, consisting of Bi atoms in a √3 × √3 30° reconstruction on GaAs(111). X-ray photoelectron spectroscopy shows that the Bi atoms of the honeycomb structure only bond to the underlying As atoms. This is supported by calculations based on density functional theory that confirm the honeycomb structure with a large Bi-As binding energy and predict Bi-induced electronic bands within the GaAs band gap that open up a gap of nontrivial topological nature. STS results support the existence of Bi-induced states within the GaAs band gap. The GaAs:Bi honeycomb layer found here has a similar structure as previously published bismuthene on SiC or on Ag, though with a significantly larger lattice constant and only weak Bi-Bi bonding. It can therefore be considered as an extreme case of bismuthene, which is fundamentally interesting. Furthermore, it has the same exciting electronic properties, opening a large nontrivial gap, which is the requirement for room-temperature spintronic applications, and it is directly integrated in GaAs, a direct band gap semiconductor with a large range of (opto)electronic devices.
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Affiliation(s)
- Yi Liu
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Sandra Benter
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Chin Shen Ong
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Renan P. Maciel
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
| | - Linnéa Björk
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Austin Irish
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Olle Eriksson
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, 751 20 Uppsala, Sweden
- School
of Science and Technology, Örebro
University, Fakultetsgatan
1, SE-70182 Örebro, Sweden
| | - Anders Mikkelsen
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - Rainer Timm
- NanoLund
and Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
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6
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Thangaraj C, Easwaramoorthy D. Fractals via Controlled Fisher Iterated Function System. FRACTAL AND FRACTIONAL 2022; 6:746. [DOI: 10.3390/fractalfract6120746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
This paper explores the generalization of the fixed-point theorem for Fisher contraction on controlled metric space. The controlled metric space and Fisher contractions are playing a very crucial role in this research. The Fisher contraction on the controlled metric space is used in this paper to generate a new type of fractal set called controlled Fisher fractals (CF-Fractals) by constructing a system named the controlled Fisher iterated function system (CF-IFS). Furthermore, the interesting results and consequences of the controlled Fisher iterated function system and controlled Fisher fractals are demonstrated. In addition, the collage theorem on controlled Fisher fractals is established as well. The newly developing IFS and fractal set in the controlled metric space can provide the novel directions in the fractal theory.
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7
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Li J, Mo Q, Jiang JH, Yang Z. Higher-order topological phase in an acoustic fractal lattice. Sci Bull (Beijing) 2022; 67:2040-2044. [PMID: 36546100 DOI: 10.1016/j.scib.2022.09.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/19/2022] [Accepted: 09/22/2022] [Indexed: 01/07/2023]
Affiliation(s)
- Junkai Li
- Department of Physics, Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310058, China
| | - Qingyang Mo
- Department of Physics, Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310058, China
| | - Jian-Hua Jiang
- School of Physical Science and Technology, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215031, China
| | - Zhaoju Yang
- Department of Physics, Interdisciplinary Center for Quantum Information and Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310058, China.
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8
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Zheng S, Man X, Kong ZL, Lin ZK, Duan G, Chen N, Yu D, Jiang JH, Xia B. Observation of fractal higher-order topological states in acoustic metamaterials. Sci Bull (Beijing) 2022; 67:2069-2075. [DOI: 10.1016/j.scib.2022.09.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/20/2022] [Accepted: 09/16/2022] [Indexed: 10/14/2022]
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9
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Wang B, Wang J, Niu X. Growth mechanism and self-polarization of bilayer InSb (111) on Bi (001) substrate. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:335001. [PMID: 35675806 DOI: 10.1088/1361-648x/ac7700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Polarity introduced by inversion symmetry broken along <111> direction has strong impacts on the physical properties and morphological characteristics of III-V component nanostructure. Take III-V component semiconductor InSb as an example, we systematically investigate the growth sequence and morphology evolution of InSb (111) on Bi (001) substrate from adatoms to bilayers. We discovered and verified that the presence of amorphous-like morphology of monolayer InSb was attributed to the strong interaction between mix-polarity InSb and Bi substrate. Further, our comprehensive energy investigations of bilayer InSb reveal that an amorphous first layer will be crystallized and polarized driven by the low surface energy of the reconstructed second layers. Phase diagrams were developed to describe the ongoing polarization process of bilayer InSb under various chemical environments as a function of deposition time. The growth mechanism and polarity phase diagram of bilayer InSb on Bi substrate may advance the progress of polarity controllable growth of low-dimensional InSb nanostructure as well as other polar III-V compound semiconductors.
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Affiliation(s)
- Bojun Wang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, People's Republic of China
| | - Jianwei Wang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, People's Republic of China
| | - Xiaobin Niu
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, People's Republic of China
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10
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Biesenthal T, Maczewsky LJ, Yang Z, Kremer M, Segev M, Szameit A, Heinrich M. Fractal photonic topological insulators. Science 2022; 376:1114-1119. [PMID: 35549309 DOI: 10.1126/science.abm2842] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Topological insulators constitute a novel state of matter with scatter-free edge states surrounding an insulating bulk. Conventional wisdom regards the insulating bulk as essential, since the invariants describing the topological properties of the system are defined therein. Here, we study fractal topological insulators based on exact fractals comprised exclusively of edge sites. We present experimental proof that, despite the lack of bulk bands, photonic lattices of helical waveguides support topologically protected chiral edge states. We show that light transport in our topological fractal system features increased velocities compared to the corresponding honeycomb lattice. By going beyond the confines of the bulk-boundary correspondence, our findings pave the way toward an expanded perception of topological insulators and open a new chapter of topological fractals.
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Affiliation(s)
- Tobias Biesenthal
- Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Lukas J Maczewsky
- Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Zhаoju Yang
- Interdisciplinary Center for Quantum Information, Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, Zhejiang Province, China
| | - Mark Kremer
- Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Mordechai Segev
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Electrical Engineering Department, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Alexander Szameit
- Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Matthias Heinrich
- Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
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