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Grzeszczyk M, Szpakowski J, Slobodeniuk AO, Kazimierczuk T, Bhatnagar M, Taniguchi T, Watanabe K, Kossacki P, Potemski M, Babiński A, Molas MR. The optical response of artificially twisted MoS[Formula: see text] bilayers. Sci Rep 2021; 11:17037. [PMID: 34426607 PMCID: PMC8382769 DOI: 10.1038/s41598-021-95700-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom-the interlayer twist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS[Formula: see text] encapsulated in hexagonal BN with interlayer twist angle ranging from 0[Formula: see text] to 60[Formula: see text] using Raman scattering and photoluminescence spectroscopies. It is found that the strength of the interlayer coupling in the studied BLs can be estimated using the energy dependence of indirect emission versus the A[Formula: see text]-E[Formula: see text] energy separation. Due to the hybridization of electronic states in the valence band, the emission line related to the interlayer exciton is apparent in both the natural (2H) and artificial (62[Formula: see text]) MoS[Formula: see text] BLs, while it is absent in the structures with other twist angles. The interlayer coupling energy is estimated to be of about 50 meV. The effect of temperature on energies and intensities of the direct and indirect emission lines in MoS[Formula: see text] BLs is also quantified.
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52
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Lackner L, Dusel M, Egorov OA, Han B, Knopf H, Eilenberger F, Schröder S, Watanabe K, Taniguchi T, Tongay S, Anton-Solanas C, Höfling S, Schneider C. Tunable exciton-polaritons emerging from WS 2 monolayer excitons in a photonic lattice at room temperature. Nat Commun 2021; 12:4933. [PMID: 34400620 PMCID: PMC8368091 DOI: 10.1038/s41467-021-24925-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 07/01/2021] [Indexed: 11/30/2022] Open
Abstract
Engineering non-linear hybrid light-matter states in tailored lattices is a central research strategy for the simulation of complex Hamiltonians. Excitons in atomically thin crystals are an ideal active medium for such purposes, since they couple strongly with light and bear the potential to harness giant non-linearities and interactions while presenting a simple sample-processing and room temperature operability. We demonstrate lattice polaritons, based on an open, high-quality optical cavity, with an imprinted photonic lattice strongly coupled to excitons in a WS2 monolayer. We experimentally observe the emergence of the canonical band-structure of particles in a one-dimensional lattice at room temperature, and demonstrate frequency reconfigurability over a spectral window exceeding 85 meV, as well as the systematic variation of the nearest-neighbour coupling, reflected by a tunability in the bandwidth of the p-band polaritons by 7 meV. The technology presented in this work is a critical demonstration towards reconfigurable photonic emulators operated with non-linear photonic fluids, offering a simple experimental implementation and working at ambient conditions.
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Takatsu H, Onoda S, Kittaka S, Kasahara A, Kono Y, Sakakibara T, Kato Y, Fåk B, Ollivier J, Lynn JW, Taniguchi T, Wakita M, Kadowaki H. Erratum: Quadrupole Order in the Frustrated Pyrochlore Tb_{2+x}Ti_{2-x}O_{7+y} [Phys. Rev. Lett. 116, 217201 (2016)]. PHYSICAL REVIEW LETTERS 2021; 127:069902. [PMID: 34420355 DOI: 10.1103/physrevlett.127.069902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Indexed: 06/13/2023]
Abstract
This corrects the article DOI: 10.1103/PhysRevLett.116.217201.
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Tanaka O, Taniguchi T, Ono K, Nakaya S, Makita C, Matsuo M, Kiryu T. PO-1858 Adrenal SBRT: The Effects of a Full and Empty Stomach on Radiation Dose to Organs at Risk. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)08309-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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55
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Phinney IY, Bandurin DA, Collignon C, Dmitriev IA, Taniguchi T, Watanabe K, Jarillo-Herrero P. Strong Interminivalley Scattering in Twisted Bilayer Graphene Revealed by High-Temperature Magneto-Oscillations. PHYSICAL REVIEW LETTERS 2021; 127:056802. [PMID: 34397232 DOI: 10.1103/physrevlett.127.056802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Twisted bilayer graphene (TBG) provides an example of a system in which the interplay of interlayer interactions and superlattice structure impacts electron transport in a variety of nontrivial ways and gives rise to a plethora of interesting effects. Understanding the mechanisms of electron scattering in TBG has, however, proven challenging, raising many questions about the origins of resistivity in this system. Here we show that TBG exhibits high-temperature magneto-oscillations originating from the scattering of charge carriers between TBG minivalleys. The amplitude of these oscillations reveals that interminivalley scattering is strong, and its characteristic timescale is comparable to that of its intraminivalley counterpart. Furthermore, by exploring the temperature dependence of these oscillations, we estimate the electron-electron collision rate in TBG and find that it exceeds that of monolayer graphene. Our study demonstrates the consequences of the relatively small size of the superlattice Brillouin zone and Fermi velocity reduction on lateral transport in TBG.
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56
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Moreau N, Brun B, Somanchi S, Watanabe K, Taniguchi T, Stampfer C, Hackens B. Upstream modes and antidots poison graphene quantum Hall effect. Nat Commun 2021; 12:4265. [PMID: 34253725 PMCID: PMC8275581 DOI: 10.1038/s41467-021-24481-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/17/2021] [Indexed: 11/09/2022] Open
Abstract
The quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semi-conductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.
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57
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Tangkonda E, Kubo M, Sekiguchi S, Shinki T, Sasaki S, Yamada K, Taniguchi T, Vetchapitak T, Misawa N. Work-related increases in titer of Campylobacter jejuni antibody among workers at a chicken processing plant in Miyazaki prefecture, Japan, independent of individual ingestion of edible raw chicken meat. J Vet Med Sci 2021; 83:1306-1314. [PMID: 34219072 PMCID: PMC8437720 DOI: 10.1292/jvms.21-0244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Workers in poultry abattoirs may be frequently exposed to Campylobacter jejuni, which is a leading cause of bacterial food poisoning in Japan. The present study was conducted to measure the titers of IgG and IgA antibodies against C. jejuni among 104 female workers in a chicken processing plant in Miyazaki prefecture, Japan. Information regarding habitual ingestion of raw chicken meat and potential occupational risk factors was collected using a questionnaire. Acid extracts of four C. jejuni strains representing the genotypes most dominant in Miyazaki were used as antigens. The levels of both immunoglobulins measured by ELISA were not correlated with ingestion of edible raw chicken meat, the amount consumed in one sitting, or its frequency. Although age was correlated with antibody levels, the length of employment was not. Furthermore, the IgG and IgA levels in workers at the evisceration step were significantly higher than those at other locations in the plant. To identify the bacterial proteins recognized by the workers' IgG and IgA antibodies, Western blotting followed by LC/MS was conducted. Flagellin was identified as the common protein recognized in the sera of workers for whom ELISA demonstrated both the highest and lowest antibody levels. We concluded that the titers of IgG and IgA against C. jejuni in workers at the processing plant had been increased by occupational exposure to Campylobacter, regardless of raw chicken meat ingestion.
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Wu S, Zhang Z, Watanabe K, Taniguchi T, Andrei EY. Author Correction: Chern insulators, van Hove singularities and topological flat bands in magic-angle twisted bilayer graphene. NATURE MATERIALS 2021; 20:1037. [PMID: 34075204 DOI: 10.1038/s41563-021-00997-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A Correction to this paper has been published: https://doi.org/10.1038/s41563-021-00997-2.
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Schuler S, Muench JE, Ruocco A, Balci O, Thourhout DV, Sorianello V, Romagnoli M, Watanabe K, Taniguchi T, Goykhman I, Ferrari AC, Mueller T. High-responsivity graphene photodetectors integrated on silicon microring resonators. Nat Commun 2021; 12:3733. [PMID: 34145226 PMCID: PMC8213857 DOI: 10.1038/s41467-021-23436-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 04/14/2021] [Indexed: 02/05/2023] Open
Abstract
Graphene integrated photonics provides several advantages over conventional Si photonics. Single layer graphene (SLG) enables fast, broadband, and energy-efficient electro-optic modulators, optical switches and photodetectors (GPDs), and is compatible with any optical waveguide. The last major barrier to SLG-based optical receivers lies in the current GPDs' low responsivity when compared to conventional PDs. Here we overcome this by integrating a photo-thermoelectric GPD with a Si microring resonator. Under critical coupling, we achieve >90% light absorption in a ~6 μm SLG channel along a Si waveguide. Cavity-enhanced light-matter interactions cause carriers in SLG to reach ~400 K for an input power ~0.6 mW, resulting in a voltage responsivity ~90 V/W, with a receiver sensitivity enabling our GPDs to operate at a 10-9 bit-error rate, on par with mature semiconductor technology, but with a natural generation of a voltage, rather than a current, thus removing the need for transimpedance amplification, with a reduction of energy-per-bit, cost, and foot-print.
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Begum NA, Haque F, Stanlie A, Husain A, Mondal S, Nakata M, Taniguchi T, Taniguchi H, Honjo T. Phf5a regulates DNA repair in class switch recombination via p400 and histone H2A variant deposition. EMBO J 2021; 40:e106393. [PMID: 33938017 PMCID: PMC8204862 DOI: 10.15252/embj.2020106393] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 11/09/2022] Open
Abstract
Antibody class switch recombination (CSR) is a locus-specific genomic rearrangement mediated by switch (S) region transcription, activation-induced cytidine deaminase (AID)-induced DNA breaks, and their resolution by non-homologous end joining (NHEJ)-mediated DNA repair. Due to the complex nature of the recombination process, numerous cofactors are intimately involved, making it important to identify rate-limiting factors that impact on DNA breaking and/or repair. Using an siRNA-based loss-of-function screen of genes predicted to encode PHD zinc-finger-motif proteins, we identify the splicing factor Phf5a/Sf3b14b as a novel modulator of the DNA repair step of CSR. Loss of Phf5a severely impairs AID-induced recombination, but does not perturb DNA breaks and somatic hypermutation. Phf5a regulates NHEJ-dependent DNA repair by preserving chromatin integrity to elicit optimal DNA damage response and subsequent recruitment of NHEJ factors at the S region. Phf5a stabilizes the p400 histone chaperone complex at the locus, which in turn promotes deposition of H2A variant such as H2AX and H2A.Z that are critical for the early DNA damage response and NHEJ, respectively. Depletion of Phf5a or p400 blocks the repair of both AID- and I-SceI-induced DNA double-strand breaks, supporting an important contribution of this axis to programmed as well as aberrant recombination.
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Vizner Stern M, Waschitz Y, Cao W, Nevo I, Watanabe K, Taniguchi T, Sela E, Urbakh M, Hod O, Ben Shalom M. Interfacial ferroelectricity by van der Waals sliding. Science 2021; 372:eabe8177. [PMID: 34112727 DOI: 10.1126/science.abe8177] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 05/10/2021] [Indexed: 12/14/2022]
Abstract
Despite their partial ionic nature, many layered diatomic crystals avoid internal electric polarization by forming a centrosymmetric lattice at their optimal van-der-Waals stacking. Here, we report a stable ferroelectric order emerging at the interface between two naturally-grown flakes of hexagonal-boron-nitride, which are stacked together in a metastable non-centrosymmetric parallel orientation. We observe alternating domains of inverted normal polarization, caused by a lateral shift of one lattice site between the domains. Reversible polarization switching coupled to lateral sliding is achieved by scanning a biased tip above the surface. Our calculations trace the origin of the phenomenon to a subtle interplay between charge redistribution and ionic displacement, and provide intuitive insights to explore the interfacial polarization and its unique "slidetronics" switching mechanism.
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Srivastav SK, Kumar R, Spånslätt C, Watanabe K, Taniguchi T, Mirlin AD, Gefen Y, Das A. Vanishing Thermal Equilibration for Hole-Conjugate Fractional Quantum Hall States in Graphene. PHYSICAL REVIEW LETTERS 2021; 126:216803. [PMID: 34114853 DOI: 10.1103/physrevlett.126.216803] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Transport through edge channels is responsible for conduction in quantum Hall (QH) phases. Robust quantized values of charge and thermal conductances dictated by bulk topology appear when equilibration processes become dominant. We report on measurements of electrical and thermal conductances of integer and fractional QH phases, realized in hexagonal boron nitride encapsulated graphite-gated bilayer graphene devices for both electron and hole doped sides with different valley and orbital symmetries. Remarkably, for complex edges at filling factors ν=5/3 and 8/3, closely related to the paradigmatic hole-conjugate ν=2/3 phase, we find quantized thermal conductance whose values (3κ_{0}T and 4κ_{0}T, respectively where κ_{0}T is the thermal conductance quantum) are markedly inconsistent with the values dictated by topology (1κ_{0}T and 2κ_{0}T, respectively). The measured thermal conductance values remain insensitive to different symmetries, suggesting its universal nature. Our findings are supported by a theoretical analysis, which indicates that, whereas electrical equilibration at the edge is established over a finite length scale, the thermal equilibration length diverges for strong electrostatic interaction. Our results elucidate the subtle nature of crossover from coherent, mesoscopic to topology-dominated transport.
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63
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Tschirhart CL, Serlin M, Polshyn H, Shragai A, Xia Z, Zhu J, Zhang Y, Watanabe K, Taniguchi T, Huber ME, Young AF. Imaging orbital ferromagnetism in a moiré Chern insulator. Science 2021; 372:1323-1327. [PMID: 34045322 DOI: 10.1126/science.abd3190] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 05/13/2021] [Indexed: 12/23/2022]
Abstract
Electrons in moiré flat band systems can spontaneously break time-reversal symmetry, giving rise to a quantized anomalous Hall effect. In this study, we use a superconducting quantum interference device to image stray magnetic fields in twisted bilayer graphene aligned to hexagonal boron nitride. We find a magnetization of several Bohr magnetons per charge carrier, demonstrating that the magnetism is primarily orbital in nature. Our measurements reveal a large change in the magnetization as the chemical potential is swept across the quantum anomalous Hall gap, consistent with the expected contribution of chiral edge states to the magnetization of an orbital Chern insulator. Mapping the spatial evolution of field-driven magnetic reversal, we find a series of reproducible micrometer-scale domains pinned to structural disorder.
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Fukushima Y, Minamino T, Mikurino Y, Honkawa K, Horii Y, Taniguchi T, Mekata H, Sasaki Y. Effects of Theileria orientalis Infection on Health Status and Productivity of Dairy Cows Reared inside Barns. Pathogens 2021; 10:pathogens10060650. [PMID: 34073926 PMCID: PMC8225029 DOI: 10.3390/pathogens10060650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/08/2021] [Accepted: 05/21/2021] [Indexed: 12/02/2022] Open
Abstract
The objective of the present study was to investigate the effects of Theileria orientalis on the severity of anemia, the prevalence of disease within 21 days after calving and productivity in cows raised inside barns. This longitudinal observational study, which was conducted on a commercial dairy farm in Japan, involved 627 Holstein cows subjected to PCR analysis for T. orientalis. In study 1, we collected blood samples from 156 sick cows within 21 days after calving, and we found the prevalence of T. orientalis infection to be 65.4%. In study 2, we randomly selected 471 cows during the dry period and collected blood samples to conduct PCR analysis for T. orientalis and determined the prevalence of T. orientalis infection to be 69.0%. Compared with the values for the T. orientalis-uninfected group, the T. orientalis-infected cows had significantly decreased hemoglobin concentrations and hematocrit, but there were no differences in the other complete blood count indexes between the two groups. In addition, there were no differences in productivity and the prevalence of major diseases between the T. orientalis-infected and uninfected cows. In summary, T. orientalis had few effects on anemia, productivity and the health of cows raised inside a barn.
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Huang H, Lee SJ, Ikeda Y, Taniguchi T, Takahama M, Kao CC, Fujita M, Lee JS. Two-Dimensional Superconducting Fluctuations Associated with Charge-Density-Wave Stripes in La_{1.87}Sr_{0.13}Cu_{0.99}Fe_{0.01}O_{4}. PHYSICAL REVIEW LETTERS 2021; 126:167001. [PMID: 33961453 DOI: 10.1103/physrevlett.126.167001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/14/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
The presence of a small concentration of in-plane Fe dopants in La_{1.87}Sr_{0.13}Cu_{0.99}Fe_{0.01}O_{4} is known to enhance stripelike spin and charge density wave (SDW and CDW) order and suppress the superconducting T_{c}. Here, we show that it also induces highly two-dimensional superconducting correlations that have been argued to be the signatures of a new form of superconducting order, the so-called pair density wave (PDW) order. In addition, using resonant soft x-ray scattering, we find that the two-dimensional superconducting fluctuation is strongly associated with the CDW stripe. In particular, the PDW signature first appears when the correlation length of the CDW stripe grows over eight times the lattice unit (∼8a). These results provide critical conditions for the formation of the PDW order.
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Taniguchi T, Latt KM, Tarigan E, Yano F, Sato H, Minamino T, Misawa N. A 1-Year Investigation of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Bovine Mastitis at a Large-Scale Dairy Farm in Japan. Microb Drug Resist 2021; 27:1450-1454. [PMID: 33900856 DOI: 10.1089/mdr.2020.0481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In a large-scale dairy farm, it is important to take countermeasure of prevention against mastitis of dairy cows, and it is especially important to establish hygiene and risk management to prevent the emergence and spread of antibiotic-resistant bacteria. In this study, we have performed bacteriological testing of clinical and subclinical mastitis and investigation of antimicrobial resistance bacteria in a large-scale farm for 1 year. The bacteria isolated most frequently from 1,549 samples of 952 cow, including cows with recurring mastitis were Staphylococcus non-aureus (SNA) (27.6%), followed by Escherichia coli (18.9%), Klebsiella pneumoniae (12.3%). Although Staphylococcus aureus was isolated at 7.7% from milk sample, no methicillin-resistant S. aureus was found. The incidence of extended-spectrum β-lactamase (ESBL)-producing E. coli was 1.4% and ESBL-producing K. pneumoniae was 1.4% of all samples, even though third- and fourth-generation cephalosporins were not used for antimicrobial treatment of mastitis in this farm. Although these genotypes of ESBL-producing E. coli and K. pneumoniae were mainly composed of CTX-M-15 and TEM-1 and CTX-M-2 and TEM-116, respectively, there was no spread and persist of predominant clonal type. Appropriate farm management, such as segregation and culling of infected animals and monitors of trends in antimicrobial resistance among mastitis pathogens, may have contributed these results.
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Khemgaew R, Omachi M, Takesada T, Vetchapitak T, Sato H, Taniguchi T, Misawa N. Transcellular penetration of Treponema phagedenis isolated from papillomatous digital dermatitis in polarized normal human epidermal keratinocytes in vitro. J Vet Med Sci 2021; 83:889-897. [PMID: 33853987 PMCID: PMC8267188 DOI: 10.1292/jvms.21-0034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Papillomatous digital dermatitis (PDD) is a polymicrobial infection causing lameness in
dairy cattle. Culture-independent analysis has shown that Treponema
phagedenis is present consistently and predominantly in the lesions. However,
the pathogenesis of PDD, especially the tissue penetration pathway, has not been examined.
In the present study, we investigated whether T. phagedenis strains
isolated from PDD produce proteolytic enzyme (s) for disruption of the epithelial cell
barrier and have the ability to translocate in polarized normal human epidermal
keratinocytes (NHEK) in vitro. Ten strains of T.
phagedenis isolated from lesions did not show proteolytic activity on modified
skim milk agar, although a human strain of T. denticola used as a control
showed such activity. The integrity of tight junctions was monitored by measurement of
transepithelial electrical resistance (TER). The TER values after inoculation of the
T. phagedenis strains examined did not change during the experimental
period; however, apical to basolateral translocation of T. phagedenis was
confirmed after 24 hr by microscopy and Treponema-specific PCR. We
further confirmed that translocation of T. phagedenis was accelerated by
co-inoculation with live T. denticola, but not with heat-killed
organisms. Furthermore, tight junction ZO-1 protein was not lost intensity after
inoculation with T. phagedenis and the organism was observed in NHEK
cells using a florescence microscope. These results suggest that T.
phagedenis strains may translocate via a transcellular route in
vitro and that the invasion is accelerated by other bacteria, such as
T. denticola, producing proteolytic activity.
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Garreis R, Knothe A, Tong C, Eich M, Gold C, Watanabe K, Taniguchi T, Fal'ko V, Ihn T, Ensslin K, Kurzmann A. Shell Filling and Trigonal Warping in Graphene Quantum Dots. PHYSICAL REVIEW LETTERS 2021; 126:147703. [PMID: 33891439 DOI: 10.1103/physrevlett.126.147703] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Transport measurements through a few-electron circular quantum dot in bilayer graphene display bunching of the conductance resonances in groups of four, eight, and twelve. This is in accordance with the spin and valley degeneracies in bilayer graphene and an additional threefold "minivalley degeneracy" caused by trigonal warping. For small electron numbers, implying a small dot size and a small displacement field, a two-dimensional s shell and then a p shell are successively filled with four and eight electrons, respectively. For electron numbers larger than 12, as the dot size and the displacement field increase, the single-particle ground state evolves into a threefold degenerate minivalley ground state. A transition between these regimes is observed in our measurements and can be described by band-structure calculations. Measurements in the magnetic field confirm Hund's second rule for spin filling of the quantum dot levels, emphasizing the importance of exchange interaction effects.
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Jo M, Brasseur P, Assouline A, Fleury G, Sim HS, Watanabe K, Taniguchi T, Dumnernpanich W, Roche P, Glattli DC, Kumada N, Parmentier FD, Roulleau P. Quantum Hall Valley Splitters and a Tunable Mach-Zehnder Interferometer in Graphene. PHYSICAL REVIEW LETTERS 2021; 126:146803. [PMID: 33891444 DOI: 10.1103/physrevlett.126.146803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
Graphene is a very promising test bed for the field of electron quantum optics. However, a fully tunable and coherent electronic beam splitter is still missing. We report the demonstration of electronic beam splitters in graphene that couple quantum Hall edge channels having opposite valley polarizations. The electronic transmission of our beam splitters can be tuned from zero to near unity. By independently setting the beam splitters at the two corners of a graphene p-n junction to intermediate transmissions, we realize a fully tunable electronic Mach-Zehnder interferometer. This tunability allows us to unambiguously identify the quantum interferences due to the Mach-Zehnder interferometer, and to study their dependence with the beam-splitter transmission and the interferometer bias voltage. The comparison with conventional semiconductor interferometers points toward universal processes driving the quantum decoherence in those two different 2D systems, with graphene being much more robust to their effect.
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Wu S, Zhang Z, Watanabe K, Taniguchi T, Andrei EY. Chern insulators, van Hove singularities and topological flat bands in magic-angle twisted bilayer graphene. NATURE MATERIALS 2021; 20:488-494. [PMID: 33589799 DOI: 10.1038/s41563-020-00911-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 12/14/2020] [Indexed: 05/12/2023]
Abstract
Magic-angle twisted bilayer graphene exhibits intriguing quantum phase transitions triggered by enhanced electron-electron interactions when its flat bands are partially filled. However, the phases themselves and their connection to the putative non-trivial topology of the flat bands are largely unexplored. Here we report transport measurements revealing a succession of doping-induced Lifshitz transitions that are accompanied by van Hove singularities, which facilitate the emergence of correlation-induced gaps and topologically non-trivial subbands. In the presence of a magnetic field, well-quantized Hall plateaus at a filling of 1,2,3 carriers per moiré cell reveal the subband topology and signal the emergence of Chern insulators with Chern numbers, C = 3,2,1, respectively. Surprisingly, for magnetic fields exceeding 5 T we observe a van Hove singularity at a filling of 3.5, suggesting the possibility of a fractional Chern insulator. This van Hove singularity is accompanied by a crossover from low-temperature metallic, to high-temperature insulating behaviour, characteristic of entropically driven Pomeranchuk-like transitions.
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Liu X, Wang Z, Watanabe K, Taniguchi T, Vafek O, Li JIA. Tuning electron correlation in magic-angle twisted bilayer graphene using Coulomb screening. Science 2021; 371:1261-1265. [PMID: 33737488 DOI: 10.1126/science.abb8754] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 02/08/2021] [Indexed: 12/24/2022]
Abstract
Controlling the strength of interactions is essential for studying quantum phenomena emerging in systems of correlated fermions. We introduce a device geometry whereby magic-angle twisted bilayer graphene is placed in close proximity to a Bernal bilayer graphene, separated by a 3-nanometer-thick barrier. By using charge screening from the Bernal bilayer, the strength of electron-electron Coulomb interaction within the twisted bilayer can be continuously tuned. Transport measurements show that tuning Coulomb screening has opposite effects on the insulating and superconducting states: As Coulomb interaction is weakened by screening, the insulating states become less robust, whereas the stability of superconductivity at the optimal doping is enhanced. The results provide important constraints on theoretical models for understanding the mechanism of superconductivity in magic-angle twisted bilayer graphene.
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72
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Yao K, Finney NR, Zhang J, Moore SL, Xian L, Tancogne-Dejean N, Liu F, Ardelean J, Xu X, Halbertal D, Watanabe K, Taniguchi T, Ochoa H, Asenjo-Garcia A, Zhu X, Basov DN, Rubio A, Dean CR, Hone J, Schuck PJ. Enhanced tunable second harmonic generation from twistable interfaces and vertical superlattices in boron nitride homostructures. SCIENCE ADVANCES 2021; 7:7/10/eabe8691. [PMID: 33658203 PMCID: PMC7929500 DOI: 10.1126/sciadv.abe8691] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/19/2021] [Indexed: 05/20/2023]
Abstract
Broken symmetries induce strong even-order nonlinear optical responses in materials and at interfaces. Unlike conventional covalently bonded nonlinear crystals, van der Waals (vdW) heterostructures feature layers that can be stacked at arbitrary angles, giving complete control over the presence or lack of inversion symmetry at a crystal interface. Here, we report highly tunable second harmonic generation (SHG) from nanomechanically rotatable stacks of bulk hexagonal boron nitride (BN) crystals and introduce the term twistoptics to describe studies of optical properties in twistable vdW systems. By suppressing residual bulk effects, we observe SHG intensity modulated by a factor of more than 50, and polarization patterns determined by moiré interface symmetry. Last, we demonstrate greatly enhanced conversion efficiency in vdW vertical superlattice structures with multiple symmetry-broken interfaces. Our study paves the way for compact twistoptics architectures aimed at efficient tunable frequency conversion and demonstrates SHG as a robust probe of buried vdW interfaces.
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73
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Robert C, Dery H, Ren L, Van Tuan D, Courtade E, Yang M, Urbaszek B, Lagarde D, Watanabe K, Taniguchi T, Amand T, Marie X. Measurement of Conduction and Valence Bands g-Factors in a Transition Metal Dichalcogenide Monolayer. PHYSICAL REVIEW LETTERS 2021; 126:067403. [PMID: 33635701 DOI: 10.1103/physrevlett.126.067403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
The electron valley and spin degree of freedom in monolayer transition-metal dichalcogenides can be manipulated in optical and transport measurements performed in magnetic fields. The key parameter for determining the Zeeman splitting, namely, the separate contribution of the electron and hole g factor, is inaccessible in most measurements. Here we present an original method that gives access to the respective contribution of the conduction and valence band to the measured Zeeman splitting. It exploits the optical selection rules of exciton complexes, in particular the ones involving intervalley phonons, avoiding strong renormalization effects that compromise single particle g-factor determination in transport experiments. These studies yield a direct determination of single band g factors. We measure g_{c1}=0.86±0.1, g_{c2}=3.84±0.1 for the bottom (top) conduction bands and g_{v}=6.1±0.1 for the valence band of monolayer WSe_{2}. These measurements are helpful for quantitative interpretation of optical and transport measurements performed in magnetic fields. In addition, the measured g factors are valuable input parameters for optimizing band structure calculations of these 2D materials.
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74
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Gayduchenko I, Xu SG, Alymov G, Moskotin M, Tretyakov I, Taniguchi T, Watanabe K, Goltsman G, Geim AK, Fedorov G, Svintsov D, Bandurin DA. Tunnel field-effect transistors for sensitive terahertz detection. Nat Commun 2021; 12:543. [PMID: 33483488 PMCID: PMC7822863 DOI: 10.1038/s41467-020-20721-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/16/2020] [Indexed: 11/09/2022] Open
Abstract
The rectification of electromagnetic waves to direct currents is a crucial process for energy harvesting, beyond-5G wireless communications, ultra-fast science, and observational astronomy. As the radiation frequency is raised to the sub-terahertz (THz) domain, ac-to-dc conversion by conventional electronics becomes challenging and requires alternative rectification protocols. Here, we address this challenge by tunnel field-effect transistors made of bilayer graphene (BLG). Taking advantage of BLG's electrically tunable band structure, we create a lateral tunnel junction and couple it to an antenna exposed to THz radiation. The incoming radiation is then down-converted by the tunnel junction nonlinearity, resulting in high responsivity (>4 kV/W) and low-noise (0.2 pW/[Formula: see text]) detection. We demonstrate how switching from intraband Ohmic to interband tunneling regime can raise detectors' responsivity by few orders of magnitude, in agreement with the developed theory. Our work demonstrates a potential application of tunnel transistors for THz detection and reveals BLG as a promising platform therefor.
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75
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Jadczak J, Kutrowska-Girzycka J, Bieniek M, Kazimierczuk T, Kossacki P, Schindler JJ, Debus J, Watanabe K, Taniguchi T, Ho CH, Wójs A, Hawrylak P, Bryja L. Probing negatively charged and neutral excitons in MoS 2/hBN and hBN/MoS 2/hBN van der Waals heterostructures. NANOTECHNOLOGY 2021; 32:145717. [PMID: 33463532 DOI: 10.1088/1361-6528/abd507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
High-quality van der Waals heterostructures assembled from hBN-encapsulated monolayer transition metal dichalcogenides enable observations of subtle optical and spin-valley properties whose identification was beyond the reach of structures exfoliated directly on standard SiO2/Si substrates. Here, we describe different van der Waals heterostructures based on uncapped single-layer MoS2 stacked onto hBN layers of different thicknesses and hBN-encapsulated monolayers. Depending on the doping level, they reveal the fine structure of excitonic complexes, i.e. neutral and charged excitons. In the emission spectra of a particular MoS2/hBN heterostructure without an hBN cap we resolve two trion peaks, T1 and T2, energetically split by about 10 meV, resembling the pair of singlet and triplet trion peaks (T S and T T ) in tungsten-based materials. The existence of these trion features suggests that monolayer MoS2 has a dark excitonic ground state, despite having a 'bright' single-particle arrangement of spin-polarized conduction bands. In addition, we show that the effective excitonic g-factor significantly depends on the electron concentration and reaches the lowest value of -2.47 for hBN-encapsulated structures, which reveals a nearly neutral doping regime. In the uncapped MoS2 structures, the excitonic g-factor varies from -1.15 to -1.39 depending on the thickness of the bottom hBN layer and decreases as a function of rising temperature.
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Talanov AV, Waissman J, Taniguchi T, Watanabe K, Kim P. High-bandwidth, variable-resistance differential noise thermometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:014904. [PMID: 33514211 DOI: 10.1063/5.0026488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/30/2020] [Indexed: 06/12/2023]
Abstract
We have developed Johnson noise thermometry applicable to mesoscopic devices with variable source impedance with high bandwidth for fast data acquisition. By implementing differential noise measurement and two-stage impedance matching, we demonstrate noise measurement in the frequency range of 120 MHz-250 MHz with a wide sample resistance range of 30 Ω-100 kΩ tuned by gate voltages and temperature. We employed high-frequency, single-ended low noise amplifiers maintained at a constant cryogenic temperature in order to maintain the desired low noise temperature. We have achieved thermometer calibration with temperature precision up to 650 μK measuring a 200 mK temperature modulation on a 10 K background with 30 s of averaging. Using this differential noise thermometry technique, we measured thermal conductivity on a bilayer graphene sample spanning the metallic and semiconducting regimes in a wide resistance range, and we compared it to the electrical conductivity.
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77
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Wakamura T, Wu NJ, Chepelianskii AD, Guéron S, Och M, Ferrier M, Taniguchi T, Watanabe K, Mattevi C, Bouchiat H. Spin-Orbit-Enhanced Robustness of Supercurrent in Graphene/WS_{2} Josephson Junctions. PHYSICAL REVIEW LETTERS 2020; 125:266801. [PMID: 33449709 DOI: 10.1103/physrevlett.125.266801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
We demonstrate the enhanced robustness of the supercurrent through graphene-based Josephson junctions in which strong spin-orbit interactions (SOIs) are induced. We compare the persistence of a supercurrent at high out-of-plane magnetic fields between Josephson junctions with graphene on hexagonal boron-nitride and graphene on WS_{2}, where strong SOIs are induced via the proximity effect. We find that in the shortest junctions both systems display signatures of induced superconductivity, characterized by a suppressed differential resistance at a low current, in magnetic fields up to 1 T. In longer junctions, however, only graphene on WS_{2} exhibits induced superconductivity features in such high magnetic fields, and they even persist up to 7 T. We argue that these robust superconducting signatures arise from quasiballistic edge states stabilized by the strong SOIs induced in graphene by WS_{2}.
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78
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Mahapatra PS, Ghawri B, Garg M, Mandal S, Watanabe K, Taniguchi T, Jain M, Mukerjee S, Ghosh A. Misorientation-Controlled Cross-Plane Thermoelectricity in Twisted Bilayer Graphene. PHYSICAL REVIEW LETTERS 2020; 125:226802. [PMID: 33315457 DOI: 10.1103/physrevlett.125.226802] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 05/08/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
The introduction of "twist" or relative rotation between two atomically thin van der Waals membranes gives rise to periodic moiré potential, leading to a substantial alteration of the band structure of the planar assembly. While most of the recent experiments primarily focus on the electronic-band hybridization by probing in-plane transport properties, here we report out-of-plane thermoelectric measurements across the van der Waals gap in twisted bilayer graphene, which exhibits an interplay of twist-dependent interlayer electronic and phononic hybridization. We show that at large twist angles, the thermopower is entirely driven by a novel phonon-drag effect at subnanometer scale, while the electronic component of the thermopower is recovered only when the misorientation between the layers is reduced to <6°. Our experiment shows that cross-plane thermoelectricity at low angles is exceptionally sensitive to the nature of band dispersion and may provide fundamental insights into the coherence of electronic states in twisted bilayer graphene.
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79
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Lyons TP, Gillard D, Molina-Sánchez A, Misra A, Withers F, Keatley PS, Kozikov A, Taniguchi T, Watanabe K, Novoselov KS, Fernández-Rossier J, Tartakovskii AI. Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe 2/CrBr 3 van der Waals heterostructures. Nat Commun 2020; 11:6021. [PMID: 33244001 PMCID: PMC7691354 DOI: 10.1038/s41467-020-19816-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/30/2020] [Indexed: 11/18/2022] Open
Abstract
Semiconducting ferromagnet-nonmagnet interfaces in van der Waals heterostructures present a unique opportunity to investigate magnetic proximity interactions dependent upon a multitude of phenomena including valley and layer pseudospins, moiré periodicity, or exceptionally strong Coulomb binding. Here, we report a charge-state dependency of the magnetic proximity effects between MoSe2 and CrBr3 in photoluminescence, whereby the valley polarization of the MoSe2 trion state conforms closely to the local CrBr3 magnetization, while the neutral exciton state remains insensitive to the ferromagnet. We attribute this to spin-dependent interlayer charge transfer occurring on timescales between the exciton and trion radiative lifetimes. Going further, we uncover by both the magneto-optical Kerr effect and photoluminescence a domain-like spatial topography of contrasting valley polarization, which we infer to be labyrinthine or otherwise highly intricate, with features smaller than 400 nm corresponding to our optical resolution. Our findings offer a unique insight into the interplay between short-lived valley excitons and spin-dependent interlayer tunneling, while also highlighting MoSe2 as a promising candidate to optically interface with exotic spin textures in van der Waals structures.
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80
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Barrier J, Kumaravadivel P, Krishna Kumar R, Ponomarenko LA, Xin N, Holwill M, Mullan C, Kim M, Gorbachev RV, Thompson MD, Prance JR, Taniguchi T, Watanabe K, Grigorieva IV, Novoselov KS, Mishchenko A, Fal'ko VI, Geim AK, Berdyugin AI. Long-range ballistic transport of Brown-Zak fermions in graphene superlattices. Nat Commun 2020; 11:5756. [PMID: 33188210 PMCID: PMC7666116 DOI: 10.1038/s41467-020-19604-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/30/2020] [Indexed: 11/12/2022] Open
Abstract
In quantizing magnetic fields, graphene superlattices exhibit a complex fractal spectrum often referred to as the Hofstadter butterfly. It can be viewed as a collection of Landau levels that arise from quantization of Brown-Zak minibands recurring at rational (p/q) fractions of the magnetic flux quantum per superlattice unit cell. Here we show that, in graphene-on-boron-nitride superlattices, Brown-Zak fermions can exhibit mobilities above 106 cm2 V−1 s−1 and the mean free path exceeding several micrometers. The exceptional quality of our devices allows us to show that Brown-Zak minibands are 4q times degenerate and all the degeneracies (spin, valley and mini-valley) can be lifted by exchange interactions below 1 K. We also found negative bend resistance at 1/q fractions for electrical probes placed as far as several micrometers apart. The latter observation highlights the fact that Brown-Zak fermions are Bloch quasiparticles propagating in high fields along straight trajectories, just like electrons in zero field. Here, the authors show that Brown-Zak fermions in graphene-on-boron-nitride superlattices exhibit mobilities above 106 cm2/V s and micrometer scale ballistic transport.
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81
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Tatsukawa F, Nohara R, Taniguchi T, Goto A, Misawa N, Katamoto H. Detection of Mycoplasma wenyonii and "Candidatus Mycoplasma haemobos" from Japanese Black breeding cows in Kyushu and Okinawa region, southern part of Japan. J Vet Med Sci 2020; 83:9-16. [PMID: 33162434 PMCID: PMC7870408 DOI: 10.1292/jvms.20-0505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to elucidate the epidemiological status of hemoplasma infection and investigate the interaction between Theileria orientalis
and hemoplasmas in Japanese Black breeding cows raised in the Kyushu and Okinawa regions. Blood samples were collected from 400 cows from 80 different farms in
eight prefectures (five samples per farm and 10 farms per prefecture). Mycoplasma wenyonii (Mw), “Candidatus Mycoplasma
haemobos” (CMh), and T. orientalis were examined by polymerase chain reaction (PCR) assay using whole blood samples. PCR results showed that
91.5% (366/400) of cows were positive for bovine hemoplasma: 40.3% were infected with Mw only, 9.5% with CMh only, and 41.8% with both species. T.
orientalis was detected in 36% (144/400) of cows. The infection rate of T. orientalis was higher in the grazing group
(P<0.001) than in the housed group, while the rate of CMh infection was higher (P<0.05) in the housed group than in
the grazing group, suggesting that not only the tick but also other arthropod vectors may contribute to hemoplasma transmission. Although the cows with
hemoplasma dual infection showed higher (P<0.05) white blood cell counts compared with hemoplasma-negative cows, there was no difference in
hematologic parameters related to the anemia between the hemoplasma-positive and -negative animals. This may indicate that Japanese Black cattle could have
resistance to the anemia caused by infection with hemoplasma.
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82
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Ishizu K, Takiguchi H, Ito S, Taniguchi T, Kawaguchi T, Hayashi M, Isotani A, Yamaji K, Shirai S, Ando K. Impact of tapered-shaped left ventricular outflow tract on permanent pacemaker implantation after the third-generation balloon-expandable valve implantation. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.2590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
In the era of transcatheter aortic valve implantation (TAVI) for patients with lower surgical risk, conduction disturbances requiring permanent pacemaker implantation (PPI) after TAVI remain a serious concern. The association between tapered-shaped left ventricular outflow tract (LVOT) and PPI after TAVI has not been elucidated.
Purposes
This study sought to identify predictors for PPI after TAVI with the third-generation balloon-expandable valve, with focus on LVOT morphology.
Methods
Of 272 consecutive patients treated with the third-generation balloon-expandable valve, 256 patients without previous PPI or bicuspid valve were retrospectively analyzed.
Results
PPI was implanted after TAVI in 20 (7.8%) patients. Patients requiring PPI had smaller LVOT area (356.3 mm2 vs. 399.4 mm2, p=0.011). Moreover, receiver-operating characteristic (ROC) statistics showed that LVOT area /annulus area possessed significantly higher predictive ability than LVOT area (area under the curve: 0.91 [95% confidence interval [CI]: 0.84 to 0.95] vs. 0.67 [95% CI: 0.57 to 0.77], p<0.001). Multivariable analysis revealed LVOT area /annulus area (odds ratio [OR]: 1.93 [95% CI: 1.38–2.71]; p<0.001 per % of decreasing), the difference between membranous septum length and implantation depth (ΔMSID) (OR: 6.82 [95% CI 2.39–19.48]; p<0.001 per mm of decreasing) and pre-existing complete right bundle branch block (CRBBB) (OR: 32.38 [95% CI 2.30–455.63]; p=0.002) as independent predictors of PPI. Further analysis using ROC statistics revealed LVOT area / annulus area of 88.5% and ΔMSID of 1.8 mm as the optimal cutoff points for prediction of PPI after the third-generation balloon-expandable valve implantation, with high negative predictive values of 98.1% and 99.0%, respectively. Figure shows the PPI rates stratified by the number of following predictors: LVOT area /annulus area <88.5%, ΔMSID <1.8 mm and pre-existing CRBBB. Patients with 2 or more predictors had significantly higher PPI rates than those with 1 or less predictor (67% [18 of 27 patients] vs. 1% [2 of 229 patients], p<0.001).
Conclusions
LVOT area /annulus area, ΔMSID and pre-existing CRBBB were identified as powerful independent predictors for PPI after TAVI. Higher valve implantation is important to prevent excessive PPI especially for patients with pre-procedural tapered-shaped LVOT, short membranous septum or pre-existing CRBBB.
PPI rates stratified by predictors
Funding Acknowledgement
Type of funding source: None
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Noda K, Kitagawa K, Miki T, Horiguchi M, Akama TO, Taniguchi T, Taniguchi H, Takahashi K, Ogra Y, Mecham RP, Terajima M, Yamauchi M, Nakamura T. A matricellular protein fibulin-4 is essential for the activation of lysyl oxidase. SCIENCE ADVANCES 2020; 6:6/48/eabc1404. [PMID: 33239290 PMCID: PMC7688322 DOI: 10.1126/sciadv.abc1404] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Fibulin-4 is a matricellular protein required for extracellular matrix (ECM) assembly. Mice deficient in fibulin-4 (Fbln4-/- ) have disrupted collagen and elastin fibers and die shortly after birth from aortic and diaphragmatic rupture. The function of fibulin-4 in ECM assembly, however, remains elusive. Here, we show that fibulin-4 is required for the activity of lysyl oxidase (LOX), a copper-containing enzyme that catalyzes the covalent cross-linking of elastin and collagen. LOX produced by Fbln4-/- cells had lower activity than LOX produced by wild-type cells due to the absence of lysine tyrosyl quinone (LTQ), a unique cofactor required for LOX activity. Our studies showed that fibulin-4 is required for copper ion transfer from the copper transporter ATP7A to LOX in the trans-Golgi network (TGN), which is a necessary step for LTQ formation. These results uncover a pivotal role for fibulin-4 in the activation of LOX and, hence, in ECM assembly.
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Taniguchi T, Ohki M, Urata A, Ohshiro S, Tarigan E, Kiatsomphob S, Vetchapitak T, Sato H, Misawa N. Detection and identification of adhesins involved in adhesion of Campylobacter jejuni to chicken skin. Int J Food Microbiol 2020; 337:108929. [PMID: 33157488 DOI: 10.1016/j.ijfoodmicro.2020.108929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/10/2020] [Accepted: 10/13/2020] [Indexed: 02/03/2023]
Abstract
Campylobacter jejuni is the leading cause of bacterial food poisoning worldwide. Chickens are considered to be one of the major reservoirs of Campylobacter infection in humans due to colonization of their intestinal tract. When the chickens are slaughtered and processed, the entire skin of the carcass becomes contaminated with campylobacters. We observed that the number of C. jejuni attached to chicken skin was reduced significantly after treatment of the skin with sodium hydroxide followed by washing with PBS, implying that adhesion factors involved in binding to C. jejuni may exist on skin. Such potential binding-related proteins present in alkaline extracts of the skin surface were detected by a two-dimensional overlay assay and identified by liquid chromatography mass spectrometry (LC-MS). Chicken serum albumin (CSA) was identified as a major protein in these alkaline extracts and confirmed by ELISA to bind specifically to C. jejuni. Moreover, using the same approach, flagellar hook protein E (FlgE) and major outer membrane protein (MOMP) in C. jejuni were identified as bacterial adhesins that bound to the CSA. The ability to bind CSA was also confirmed using recombinant FlgE and MOMP of C. jejuni expressed in Escherichia coli. The present findings suggest that adhesins expressed on C. jejuni cells may bind specifically via proteins present on the skin, as well as by physical attachment.
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Banszerus L, Rothstein A, Fabian T, Möller S, Icking E, Trellenkamp S, Lentz F, Neumaier D, Watanabe K, Taniguchi T, Libisch F, Volk C, Stampfer C. Electron-Hole Crossover in Gate-Controlled Bilayer Graphene Quantum Dots. NANO LETTERS 2020; 20:7709-7715. [PMID: 32986437 PMCID: PMC7564435 DOI: 10.1021/acs.nanolett.0c03227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/28/2020] [Indexed: 05/21/2023]
Abstract
Electron and hole Bloch states in bilayer graphene exhibit topological orbital magnetic moments with opposite signs, which allows for tunable valley-polarization in an out-of-plane magnetic field. This property makes electron and hole quantum dots (QDs) in bilayer graphene interesting for valley and spin-valley qubits. Here, we show measurements of the electron-hole crossover in a bilayer graphene QD, demonstrating opposite signs of the magnetic moments associated with the Berry curvature. Using three layers of top gates, we independently control the tunneling barriers while tuning the occupation from the few-hole regime to the few-electron regime, crossing the displacement-field-controlled band gap. The band gap is around 25 meV, while the charging energies of the electron and hole dots are between 3 and 5 meV. The extracted valley g-factor is around 17 and leads to opposite valley polarization for electrons and holes at moderate B-fields. Our measurements agree well with tight-binding calculations for our device.
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Zinkiewicz M, Slobodeniuk AO, Kazimierczuk T, Kapuściński P, Oreszczuk K, Grzeszczyk M, Bartos M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Neutral and charged dark excitons in monolayer WS 2. NANOSCALE 2020; 12:18153-18159. [PMID: 32853305 DOI: 10.1039/d0nr04243a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.
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87
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Baek H, Brotons-Gisbert M, Koong ZX, Campbell A, Rambach M, Watanabe K, Taniguchi T, Gerardot BD. Highly energy-tunable quantum light from moiré-trapped excitons. SCIENCE ADVANCES 2020; 6:6/37/eaba8526. [PMID: 32917702 PMCID: PMC7486092 DOI: 10.1126/sciadv.aba8526] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 07/24/2020] [Indexed: 05/20/2023]
Abstract
Photon antibunching, a hallmark of quantum light, has been observed in the correlations of light from isolated atomic and atomic-like solid-state systems. Two-dimensional semiconductor heterostructures offer a unique method to create a quantum light source: Moiré trapping potentials for excitons are predicted to create arrays of quantum emitters. While signatures of moiré-trapped excitons have been observed, their quantum nature has yet to be confirmed. Here, we report photon antibunching from single moiré-trapped interlayer excitons in a heterobilayer. Via magneto-optical spectroscopy, we demonstrate that the discrete anharmonic spectra arise from bound band-edge electron-hole pairs trapped in moiré potentials. Last, we exploit the large permanent dipole of interlayer excitons to achieve large direct current (DC) Stark tuning up to 40 meV. Our results confirm the quantum nature of moiré-confined excitons and open opportunities to investigate their inhomogeneity and interactions between the emitters or energetically tune single emitters into resonance with cavity modes.
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88
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Robert C, Han B, Kapuscinski P, Delhomme A, Faugeras C, Amand T, Molas MR, Bartos M, Watanabe K, Taniguchi T, Urbaszek B, Potemski M, Marie X. Measurement of the spin-forbidden dark excitons in MoS 2 and MoSe 2 monolayers. Nat Commun 2020; 11:4037. [PMID: 32788704 PMCID: PMC7423942 DOI: 10.1038/s41467-020-17608-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/08/2020] [Indexed: 11/13/2022] Open
Abstract
Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30 T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14 meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field.
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89
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Rupprecht C, Klaas M, Knopf H, Taniguchi T, Watanabe K, Qin Y, Tongay S, Schröder S, Eilenberger F, Höfling S, Schneider C. Demonstration of a polariton step potential by local variation of light-matter coupling in a van-der-Waals heterostructure. OPTICS EXPRESS 2020; 28:18649-18657. [PMID: 32672161 DOI: 10.1364/oe.392821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
The large oscillator strength of excitons in transition metal dichalcogenide layers facilitates the formation of exciton-polariton resonances for monolayers and van-der-Waals heterostructures embedded in optical microcavities. Here, we show, that locally changing the number of layers in a WSe2/hBN/WSe2 van-der-Waals heterostructure embedded in a monolithic, high-quality-factor cavity gives rise to a local variation of the coupling strength. This effect yields a polaritonic stair case potential, which we demonstrate at room temperature. Our result paves the way towards engineering local polaritonic potentials at length scales down to atomically sharp interfaces, based on purely modifying its real part contribution via the coherent light-matter coupling strength g.
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90
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Zondiner U, Rozen A, Rodan-Legrain D, Cao Y, Queiroz R, Taniguchi T, Watanabe K, Oreg Y, von Oppen F, Stern A, Berg E, Jarillo-Herrero P, Ilani S. Cascade of phase transitions and Dirac revivals in magic-angle graphene. Nature 2020; 582:203-208. [PMID: 32528091 DOI: 10.1038/s41586-020-2373-y] [Citation(s) in RCA: 181] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/23/2020] [Indexed: 11/09/2022]
Abstract
Twisted bilayer graphene near the magic angle1-4 exhibits rich electron-correlation physics, displaying insulating3-6, magnetic7,8 and superconducting phases4-6. The electronic bands of this system were predicted1,2 to narrow markedly9,10 near the magic angle, leading to a variety of possible symmetry-breaking ground states11-17. Here, using measurements of the local electronic compressibility, we show that these correlated phases originate from a high-energy state with an unusual sequence of band population. As carriers are added to the system, the four electronic 'flavours', which correspond to the spin and valley degrees of freedom, are not filled equally. Rather, they are populated through a sequence of sharp phase transitions, which appear as strong asymmetric jumps of the electronic compressibility near integer fillings of the moiré lattice. At each transition, a single spin/valley flavour takes all the carriers from its partially filled peers, 'resetting' them to the vicinity of the charge neutrality point. As a result, the Dirac-like character observed near charge neutrality reappears after each integer filling. Measurement of the in-plane magnetic field dependence of the chemical potential near filling factor one reveals a large spontaneous magnetization, further substantiating this picture of a cascade of symmetry breaking. The sequence of phase transitions and Dirac revivals is observed at temperatures well above the onset of the superconducting and correlated insulating states. This indicates that the state that we report here, with its strongly broken electronic flavour symmetry and revived Dirac-like electronic character, is important in the physics of magic-angle graphene, forming the parent state out of which the more fragile superconducting and correlated insulating ground states emerge.
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91
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Kim M, Xu SG, Berdyugin AI, Principi A, Slizovskiy S, Xin N, Kumaravadivel P, Kuang W, Hamer M, Kumar RK, Gorbachev RV, Watanabe K, Taniguchi T, Grigorieva IV, Fal'ko VI, Polini M, Geim AK. Publisher Correction: Control of electron-electron interaction in graphene by proximity screening. Nat Commun 2020; 11:3054. [PMID: 32528007 PMCID: PMC7289850 DOI: 10.1038/s41467-020-16708-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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92
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Vetchapitak T, Shinki T, Sasaki S, Taniguchi T, Luangtongkum T, Misawa N. Evaluation of chemical treatment combined with vacuum and ultrasonication with a water resonance system for reducing Campylobacter on naturally contaminated chicken carcasses. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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93
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Banszerus L, Frohn B, Fabian T, Somanchi S, Epping A, Müller M, Neumaier D, Watanabe K, Taniguchi T, Libisch F, Beschoten B, Hassler F, Stampfer C. Observation of the Spin-Orbit Gap in Bilayer Graphene by One-Dimensional Ballistic Transport. PHYSICAL REVIEW LETTERS 2020; 124:177701. [PMID: 32412294 DOI: 10.1103/physrevlett.124.177701] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/13/2020] [Indexed: 05/21/2023]
Abstract
We report on measurements of quantized conductance in gate-defined quantum point contacts in bilayer graphene that allow the observation of subband splittings due to spin-orbit coupling. The size of this splitting can be tuned from 40 to 80 μeV by the displacement field. We assign this gate-tunable subband splitting to a gap induced by spin-orbit coupling of Kane-Mele type, enhanced by proximity effects due to the substrate. We show that this spin-orbit coupling gives rise to a complex pattern in low perpendicular magnetic fields, increasing the Zeeman splitting in one valley and suppressing it in the other one. In addition, we observe a spin polarized channel of 6e^{2}/h at high in-plane magnetic field and signatures of interaction effects at the crossings of spin-split subbands of opposite spins at finite magnetic field.
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94
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Kotani H, Ohtsuka T, Okada S, Kusama M, Taniguchi T. A case of IgG4-related disease presented with Kimura disease-like skin eruption, rheumatoid arthritis-like abnormality and interstitial pneumonia. Clin Exp Dermatol 2020; 45:733-734. [PMID: 32189363 DOI: 10.1111/ced.14222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/06/2020] [Indexed: 11/27/2022]
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95
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Berdyugin AI, Tsim B, Kumaravadivel P, Xu SG, Ceferino A, Knothe A, Kumar RK, Taniguchi T, Watanabe K, Geim AK, Grigorieva IV, Fal’ko VI. Minibands in twisted bilayer graphene probed by magnetic focusing. SCIENCE ADVANCES 2020; 6:eaay7838. [PMID: 32494602 PMCID: PMC7164947 DOI: 10.1126/sciadv.aay7838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/22/2020] [Indexed: 05/25/2023]
Abstract
Magnetic fields force ballistic electrons injected from a narrow contact to move along skipping orbits and form caustics. This leads to pronounced resistance peaks at nearby voltage probes as electrons are effectively focused inside them, a phenomenon known as magnetic focusing. This can be used not only for the demonstration of ballistic transport but also to study the electronic structure of metals. Here, we use magnetic focusing to probe narrowbands in graphene bilayers twisted at ~2°. Their minibands are found to support long-range ballistic transport limited at low temperatures by intrinsic electron-electron scattering. A voltage bias between the layers causes strong minivalley splitting and allows selective focusing for different minivalleys, which is of interest for using this degree of freedom in frequently discussed valleytronics.
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96
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Casalis de Pury A, Zheng X, Ojambati OS, Trifonov A, Grosse C, Kleemann ME, Babenko V, Purdie D, Taniguchi T, Watanabe K, Lombardo A, Vandenbosch GAE, Hofmann S, Baumberg JJ. Localized Nanoresonator Mode in Plasmonic Microcavities. PHYSICAL REVIEW LETTERS 2020; 124:093901. [PMID: 32202875 DOI: 10.1103/physrevlett.124.093901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
Submicron-thick hexagonal boron nitride crystals embedded in noble metals form planar Fabry-Perot half-microcavities. Depositing Au nanoparticles on top of these microcavities forms previously unidentified angle- and polarization-sensitive nanoresonator modes that are tightly laterally confined by the nanoparticle. Comparing dark-field scattering with reflection spectroscopies shows plasmonic and Fabry-Perot-like enhancements magnify subtle interference contributions, which lead to unexpected redshifts in the dark-field spectra, explained by the presence of these new modes.
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97
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Huang P, Riccardi E, Messelot S, Graef H, Valmorra F, Tignon J, Taniguchi T, Watanabe K, Dhillon S, Plaçais B, Ferreira R, Mangeney J. Ultra-long carrier lifetime in neutral graphene-hBN van der Waals heterostructures under mid-infrared illumination. Nat Commun 2020; 11:863. [PMID: 32054848 PMCID: PMC7018796 DOI: 10.1038/s41467-020-14714-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/27/2020] [Indexed: 12/03/2022] Open
Abstract
Graphene/hBN heterostructures are promising active materials for devices in the THz domain, such as emitters and photodetectors based on interband transitions. Their performance requires long carrier lifetimes. However, carrier recombination processes in graphene possess sub-picosecond characteristic times for large non-equilibrium carrier densities at high energy. An additional channel has been recently demonstrated in graphene/hBN heterostructures by emission of hBN hyperbolic phonon polaritons (HPhP) with picosecond decay time. Here, we report on carrier lifetimes in graphene/hBN Zener-Klein transistors of ~30 ps for photoexcited carriers at low density and energy, using mid-infrared photoconductivity measurements. We further demonstrate the switching of carrier lifetime from ~30 ps (attributed to interband Auger) down to a few picoseconds upon ignition of HPhP relaxation at finite bias and/or with infrared excitation power. Our study opens interesting perspectives to exploit graphene/hBN heterostructures for THz lasing and highly sensitive THz photodetection as well as for phonon polariton optics. Long carrier lifetimes are beneficial for graphene-based optoelectronics, but carrier recombination processes in graphene possess sub-picosecond characteristic times. Here, the authors report carrier lifetimes ~30 ps at low energy in graphene/hBN Zener-Klein transistors, attributed to interband Auger processes.
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98
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Serlin M, Tschirhart CL, Polshyn H, Zhang Y, Zhu J, Watanabe K, Taniguchi T, Balents L, Young AF. Intrinsic quantized anomalous Hall effect in a moiré heterostructure. Science 2019; 367:900-903. [PMID: 31857492 DOI: 10.1126/science.aay5533] [Citation(s) in RCA: 304] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 12/06/2019] [Indexed: 01/21/2023]
Abstract
The quantum anomalous Hall (QAH) effect combines topology and magnetism to produce precisely quantized Hall resistance at zero magnetic field. We report the observation of a QAH effect in twisted bilayer graphene aligned to hexagonal boron nitride. The effect is driven by intrinsic strong interactions, which polarize the electrons into a single spin- and valley-resolved moiré miniband with Chern number C = 1. In contrast to magnetically doped systems, the measured transport energy gap is larger than the Curie temperature for magnetic ordering, and quantization to within 0.1% of the von Klitzing constant persists to temperatures of several kelvin at zero magnetic field. Electrical currents as small as 1 nanoampere controllably switch the magnetic order between states of opposite polarization, forming an electrically rewritable magnetic memory.
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99
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Wang Z, Wang YB, Yin J, Tóvári E, Yang Y, Lin L, Holwill M, Birkbeck J, Perello DJ, Xu S, Zultak J, Gorbachev RV, Kretinin AV, Taniguchi T, Watanabe K, Morozov SV, Anđelković M, Milovanović SP, Covaci L, Peeters FM, Mishchenko A, Geim AK, Novoselov KS, Fal’ko VI, Knothe A, Woods CR. Composite super-moiré lattices in double-aligned graphene heterostructures. SCIENCE ADVANCES 2019; 5:eaay8897. [PMID: 32064323 PMCID: PMC6989342 DOI: 10.1126/sciadv.aay8897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/22/2019] [Indexed: 05/30/2023]
Abstract
When two-dimensional (2D) atomic crystals are brought into close proximity to form a van der Waals heterostructure, neighbouring crystals may influence each other's properties. Of particular interest is when the two crystals closely match and a moiré pattern forms, resulting in modified electronic and excitonic spectra, crystal reconstruction, and more. Thus, moiré patterns are a viable tool for controlling the properties of 2D materials. However, the difference in periodicity of the two crystals limits the reconstruction and, thus, is a barrier to the low-energy regime. Here, we present a route to spectrum reconstruction at all energies. By using graphene which is aligned to two hexagonal boron nitride layers, one can make electrons scatter in the differential moiré pattern which results in spectral changes at arbitrarily low energies. Further, we demonstrate that the strength of this potential relies crucially on the atomic reconstruction of graphene within the differential moiré super cell.
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100
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Taniguchi T, Hyodo F, Shimozato T, Oono K, Tanaka O, Matsuo M. PO-176: Usefulness of SBRT treatment plan combined with 99mTc-GSA for hepatocellular carcinoma. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(20)30518-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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