Article
Multidisciplinary Sciences
Andreij C. Gadelha, Douglas A. A. Ohlberg, Cassiano Rabelo, Eliel G. S. Neto, Thiago L. Vasconcelos, Joao L. Campos, Jessica S. Lemos, Vinicius Ornelas, Daniel Miranda, Rafael Nadas, Fabiano C. Santana, Kenji Watanabe, Takashi Taniguchi, Benoit van Troeye, Michael Lamparski, Vincent Meunier, Viet-Hung Nguyen, Dawid Paszko, Jean-Christophe Charlier, Leonardo C. Campos, Luiz G. Cancado, Gilberto Medeiros-Ribeiro, Ado Jorio
Summary: The twisted bilayer graphene undergoes self-organized lattice reconstruction, resulting in the formation of a superlattice that modulates vibrational and electronic structures, leading to phenomena such as strong correlations and superconductivity. Although experimental techniques and theoretical models face challenges in observing and describing these effects, nano-Raman spectroscopy can localize some vibrational modes and provide insights into the effects of electron-phonon coupling on the material properties.
Article
Chemistry, Physical
Wenxiang Liu, Yang Hong, Jingchao Zhang, Yanan Yue
Summary: This study comprehensively investigates the anisotropic thermal conductivity of twisted bilayer graphene (TBLG), revealing a strong non-monotonic correlation between thermal conductivity and twisting angles. The physical mechanism behind the decreasing thermal conductivity with increasing twisting angles is explained. The reported anisotropic thermal conductivity is important for thermal modulation and provides a valuable complement to phonon studies of TBLG.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
N. Benlakhouy, A. El Mouhafid, A. Jellal
Summary: The study investigates transport properties through a rectangular potential barrier in AB-stacked bilayer graphene gapped by dielectric layers. The results show different transmission characteristics and influencing factors under different models. Introducing inter-layer bias and considering different band models can affect the intensity and mode of transmission.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Chemistry, Physical
Hans Kuzmany, Lei Shi, Miles Martinati, Sofie Cambre, Wim Wenseleers, Jeno Kurti, Janos Koltai, Gergo Kukucska, Kecheng Cao, Ute Kaiser, Takeshi Saito, Thomas Pichler
Summary: This study demonstrates a method for synthesizing 6- and 7-armchair graphene nanoribbons with widths of 0.61 and 0.74 nm and excitonic gaps of 1.83 and 2.18 eV by high-temperature vacuum annealing of ferrocene molecules inside single-walled carbon nanotubes. The growth process is confirmed by atomic resolution electron microscopy, while the structure is identified through Raman scattering characterization and quantum-chemical calculations.
Article
Mechanics
Gianfranco Ulian, Daniele Moro, Giovanni Valdre
Summary: Graphene and MoS2 stacked composite materials have structural advantages and studies on electronic and optical properties have revealed a small direct band gap. The complex dielectric function and related properties in the visible-light spectral region of this composite material have shown significant variations.
COMPOSITE STRUCTURES
(2021)
Article
Chemistry, Physical
Thi My Duyen Huynh, Guo-Song Hung, Godfrey Gumbs, Ngoc Thanh Thuy Tran
Summary: In this study, first-principles calculations are used to investigate the feature-rich properties of alkali-metal intercalated graphene nanoribbons (GNRs), including edge passivation, stacking configurations, intercalation sites, stability, charge density distribution, magnetic configuration, and electronic properties. The findings demonstrate a transformation from finite gap semiconducting to metallic behaviors, indicating enhanced electrical conductivity. This transformation is attributed to the cooperative or competitive relations among the significant chemical bonds, finite-size quantum confinement, edge structure, and stacking order. The decoration of edge structures with hydrogen and oxygen atoms provides additional information about stability and magnetization due to the ribbons' effect.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Marijn A. M. Versteegh, Stephan Steinhauer, Josip Bajo, Thomas Lettner, Ariadna Soro, Alena Romanova, Samuel Gyger, Lucas Schweickert, Andre Mysyrowicz, Val Zwiller
Summary: Studies have shown the existence of giant Rydberg excitons in cuprous oxide at T = 38 mK, with principal quantum numbers up to 30, corresponding to a calculated diameter of 3 micrometers. Photoluminescence excitation spectroscopy can be used to probe transition probabilities between different excitonic states.
Article
Chemistry, Physical
Baekwon Park, Gyouil Jeong, Eunhak Lim, Yeonjoon Suh, Boogeon Choi, Hyeon-Woo Jeong, Kenji Watanabe, Takashi Taniguchi, Gil-Ho Lee, Jiyoung Heo, Byung Hee Hong, Zee Hwan Kim
Summary: The oxidation of bilayer graphene can be reversibly and stacking-specifically controlled, with different graphene layer stacking orders influencing the oxide structures. This discovery is crucial for designing high-performance graphene-based catalysts.
CHEMISTRY OF MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Rajesh Thakur, P. K. Ahluwalia, Ashok Kumar, Raman Sharma
Summary: The study found that triangular DLS has strong stability and can be turned into a semiconductor under the action of an electric field; hexagonal DLS is easily deformed and has better elastic response. The bilayer spiral structure exhibits intrinsic Rashba splitting.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Disha Arora, Deepanshu Aggarwal, Sankalpa Ghosh, Rohit Narula
Summary: We investigate the polarization-controlled Rayleigh scattering response of twisted bilayer graphene (tBLG) by considering the effects of structural corrugation, doping-dependent Hartree interactions, and particle-hole asymmetry. It is found that the dominant wave vectors for the Rayleigh scattering process come from different regions of the moire Brillouin zone (MBZ), in contrast to single-layer graphene (SLG) and AB-stacked bilayer graphene (AB-BLG). The integrated Rayleigh intensity is significantly enhanced for small twist angles, and the corrugation effects have a strong impact on the polarization-dependent scattering response.
Article
Chemistry, Physical
Weiyi Lin, Pingping Zhuang
Summary: This study investigates the charge distribution in bilayer graphene and reveals that the hole distribution in the top and bottom layers of AB-BLG and t-BLG are similar, with the additional layer reducing the charge exchange at the graphene/dopant interface.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Dongxu Zheng, Peng Han, Xinke Wang, Wenfeng Sun, Jiasheng Ye, Yan Zhang
Summary: Through ab initio density functional theory calculations, the lattice vibrations of graphene quantum dots (GQDs) were studied, showing a transition in vibrational properties with increasing dot size and a dependence on the symmetry of GQDs. It was found that out-of-plane vibrated standing waves induced by lateral confinement dominate the lattice vibrations of small GQDs. Coherent acoustic phonon modes in GQDs were identified, with a size dependence of frequency linked to the isotropy of nanostructures.
Article
Chemistry, Physical
Qiang Lu, Lian-Lian Zhang, Wei-Bin Cui, Shu-Feng Zhang, Wei-Jiang Gong
Summary: The study found that the Dirac-cone properties of both graphene and As-F nanosheets are well preserved in the hetero-bilayer system and their positions can be effectively tuned by strained biaxial stretching. Improved optical properties in the system suggest potential photocatalytic and photovoltaic applications.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Kyuyeon Won, Chanwoo Lee, Jaehyuck Jung, Sanghyuk Kwon, Yisehak Gebredingle, Jang Gyun Lim, Moon Ki Kim, Mun Seok Jeong, Changgu Lee
Summary: Graphene, a superstiff and extremely strong material, has been challenging to measure its physical properties under high strains. This research reports a successful measurement of suspended graphene under a biaxial strain as large as 6.1% using AFM-Raman spectroscopy. The Raman signals of graphene's G and 2D bands redshifted significantly, providing an effective methodology to measure variations in the physical properties of atomically thin materials under superhigh strain.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Physical
Ningning Xuan, Aozhen Xie, Bing Liu, Zhengzong Sun
Summary: Bilayer graphene (BLG) has attracted significant research interest for its tunable physical properties dependent on twisted angles and interlayer interaction. This article focuses on the study of BLG single crystals with representative twisted angles of approximately 0 degrees and approximately 30 degrees, grown by chemical vapor deposition (CVD). The surface potentials of pristine BLG single crystals indicate that the surface potential difference between single layer graphene (SLG) and BLG is lower for approximately 0 degrees compared to approximately 30 degrees. Additionally, reversible tuning of the electrical coupling and properties of BLG is achieved through diazonium salts reaction and nitrogen doping, resulting in a wide range of surface potential tuning from 0 to 50 mV.
Article
Polymer Science
Alexey Ermakov, Su Hui Lim, Sergey Gorelik, Alan P. Kauling, Ricardo V. B. de Oliveira, A. H. Castro Neto, Evgeniy Glukhovskoy, Dmitry A. Gorin, Gleb B. Sukhorukov, Maxim Kiryukhin
MACROMOLECULAR RAPID COMMUNICATIONS
(2019)
Article
Dentistry, Oral Surgery & Medicine
Shruti Vidhawan Agarwalla, Kassapa Ellepola, Mariana Caldeira Ferraz da Costa, Guilhermino Jose Macedo Fechine, Julien Luc Paul Morin, A. H. Castro Neto, Chaminda Jayampath Seneviratne, Vinicius Rosa
Article
Chemistry, Physical
Ana P. M. Barboza, Alan C. R. Souza, Matheus J. S. Matos, Juliana C. Brant, Tiago C. Barbosa, Helio Chacham, Mario S. C. Mazzoni, Bernardo R. A. Neves
Article
Chemistry, Multidisciplinary
Bruno R. Carvalho, Yuanxi Wang, Kazunori Fujisawa, Tianyi Zhang, Ethan Kahn, Ismail Bilgin, Pulickel M. Ajayan, Ana M. de Paula, Marcos A. Pimenta, Swastik Kar, Vincent H. Crespi, Mauricio Terrones, Leandro M. Malard
Article
Materials Science, Multidisciplinary
Geovani C. Resende, Guilherme A. S. Ribeiro, Orlando J. Silveira, Jessica S. Lemos, Juliana C. Brant, Daniel Rhodes, Luis Balicas, Mauricio Terrones, Mario S. C. Mazzoni, Cristiano Fantini, Bruno R. Carvalho, Marcos A. Pimenta
Summary: In this study, angle-dependent polarized Raman spectroscopy was used to investigate a single-layer triclinic ReSe2, revealing the physical origin of the complex nature of the Raman tensor elements through a new coordinate system. This understanding contributes to the development of new optoelectronic devices based on low-symmetry 2D materials by exploring electron-phonon coupling anisotropy.
Article
Materials Science, Multidisciplinary
Rafael N. Gontijo, Tianyi Zhang, Kazunori Fujisawa, Ana Laura Elias, Marcos A. Pimenta, Ariete Righi, Mauricio Terrones, Cristiano Fantini
Summary: In this study, Raman spectroscopy was used to investigate low-frequency defect-induced Raman bands in MoS2, revealing the influence of excitation energy and temperature on defect-induced Raman processes. Additionally, it was observed that the ratio of intensities of the DI longitudinal and transversal acoustic modes with respect to the first-order E' mode was similar for two different samples when corrected by defect density. The largest intensity of the DI peaks was found to occur for laser energies in resonance with excitonic transitions, highlighting the importance of laser excitation energy in studying defects in MoS2 samples.
Article
Physics, Applied
Rafael R. Rojas-Lopez, Juliana C. Brant, Maira S. O. Ramos, Tulio H. L. G. Castro, Marcos H. D. Guimaraes, Bernardo R. A. Neves, Paulo S. S. Guimaraes
Summary: The integration of MoS2 with GaAs results in a significant decrease in emission intensity of MoS2, with a dependence on the type of substrates observed in the trion to A-exciton emission ratio in photoluminescence spectra. Scanning Kelvin probe microscopy measurements suggest type-I band alignments, indicating the transfer of excitons from the MoS2 monolayer to the GaAs substrate. Overall, these findings shed light on the charge exchange leading to band offsets in 2D/3D heterojunctions and its implications for electronic devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Multidisciplinary Sciences
T. J. Whitcher, Angga Dito Fauzi, D. Caozheng, X. Chi, A. Syahroni, T. C. Asmara, M. B. H. Breese, A. H. Castro Neto, A. T. S. Wee, M. Aziz Majidi, A. Rusydi
Summary: This study reveals unconventional soft X-ray correlated plasmons and electronic transitions in bulk MoS2 through measuring complex dielectric and loss functions. The electronic structure shows characteristics of both 3D and 2D systems as interlayer and intralayer correlations change with temperature.
NATURE COMMUNICATIONS
(2021)
Letter
Multidisciplinary Sciences
T. J. Whitcher, A. D. Fauzi, C. Diao, X. Chi, A. Syahroni, T. C. Asmara, M. B. H. Breese, A. H. Castro Neto, A. T. S. Wee, M. A. Majidi, A. Rusydi
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jessica S. Lemos, Elena Blundo, Antonio Polimeni, Marcos A. Pimenta, Ariete Righi
Summary: This work presents a resonance Raman study conducted on the domes of monolayer MoS2, using 23 different laser excitation energies. The study reveals the exciton-phonon interactions of specific phonons (A'(1), E', and LA) with different excitonic optical transitions in strained MoS2 domes. The results show that the out-of-plane A'(1) phonon mode is significantly enhanced by the indirect exciton I and the C exciton, while the in-plane E' mode is only enhanced by the C exciton. The 2LA Raman band is significantly enhanced by the indirect exciton I and the A (or B) exciton, but not by the C exciton.
Article
Chemistry, Physical
Marcos A. Pimenta, Geovani C. Resende, Henrique B. Ribeiro, Bruno R. Carvalho
Summary: This perspective review discusses the application of polarized Raman spectroscopy in studying optically anisotropic 2D materials, highlighting the unique Raman tensor for each phonon mode and analyzing the polarization dependence of peak intensities. Specific examples of orthorhombic and monoclinic materials are presented, demonstrating the differences in Raman tensor behavior. The discussion also covers the role of complex numbers in describing Raman tensor elements and the importance of understanding the electron-phonon interaction in explaining distinct Raman tensors for each phonon mode.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Review
Materials Science, Multidisciplinary
Marcus V. O. Moutinho, Pedro Venezuela, Marcos A. Pimenta
Summary: When two periodic two-dimensional structures are superposed, a Moire pattern superlattice is generated, and this effect is crucial for materials like bilayer graphene. Raman spectroscopy is frequently used to characterize twisted bilayer graphene, revealing important effects such as the appearance of new peaks and the enhancement of G band intensity.
C-JOURNAL OF CARBON RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
Rafael N. Gontijo, Andreij Gadelha, Orlando J. Silveira, Ricardo W. Nunes, Marcos A. Pimenta, Ariete Righi, Cristiano Fantini
Summary: The study presents measurements of the resonance Raman spectra of MoS2 in different thicknesses to identify the processes related to acoustic phonons involved in intervalley scattering. By analyzing the electronic and vibrational structures of samples with different thicknesses, the study provides assignments to the Raman bands appearing around 380, 395, and 405 cm(-1). This work sheds light on the double-resonance processes of MoS2 and establishes the scattering mechanism for some two-phonon and double-resonance Raman bands.
Article
Materials Science, Multidisciplinary
Chuan Chen, Lei Su, A. H. Castro Neto, Vitor M. Pereira
Article
Pharmacology & Pharmacy
S. S. Jaganathan, Gloria Jemmi Christobel Robinson, Abirami Padmanaban, Shila Samuel, V. Radhakrishnan
Summary: This study demonstrates the potential of hesperetin as a mTOR inhibitor in both in silico and in vitro analyses. Hesperetin showed significant inhibitory effects on the phosphorylation of mTOR and downstream molecules in PA-1 and MCF-7 cancer cell lines in a dose-dependent manner.
INDIAN JOURNAL OF PHARMACEUTICAL SCIENCES
(2021)
