Article
Chemistry, Multidisciplinary
Xiao Guo, Yongsong Wang, Siwen You, Dingbang Yang, Guiping Jia, Fei Song, Weidong Dou, Han Huang
Summary: Graphene has high carrier mobility and concentration, as well as other remarkable properties. The thermal behaviors of phonon modes play important roles in the application of optical and electronic devices. This study conducted temperature-dependent Raman scattering measurements on graphene with various number of layers on different substrates and found that the substrate effect has a significant impact on the graphene phonon temperature dependence.
Article
Chemistry, Physical
Eunji Ji, Min Jung Kim, Jong-Young Lee, Dongchul Sung, Namwon Kim, Jin-Woo Park, Suklyun Hong, Gwan-Hyoung Lee
Summary: The study investigates the influence of substrate conditions on the doping and degradation of graphene, revealing that the hydroxyl groups on the oxygen-plasma-treated SiO2 substrate alter the characteristics of graphene and lead to decreased reactivity and conductivity.Graphene on P-SiO2 exhibits higher reactivity due to doping induced by -OH groups and shows reduced carrier mobility and larger shift of charge neutral point. Meanwhile, the device on the bare SiO2 shows negligible changes even after UV exposure.
Article
Engineering, Civil
Jiangtao Xue, Lihua Chen, Liqi Chang, Wei Zhang
Summary: This paper introduces a micro cantilever vibration energy harvester based on flexoelectric theory, utilizing collisions of two beams to achieve a broad bandwidth. By selecting nanocrystalline graphene as the base layer, the device demonstrates high sensitivity to external excitation and low energy loss during power conversion. Experimental results confirm that the working bandwidth of the VEH has increased approximately fourfold, and the output power density is improved in some cases.
ENGINEERING STRUCTURES
(2021)
Article
Chemistry, Physical
Luca Basta, Aldo Moscardini, Stefano Veronesi, Federica Bianco
Summary: Low energy electrons can be used to pattern structural defects in monolayer graphene sheets, and the lateral resolution is strongly influenced by the surface of the supporting substrate.
SURFACES AND INTERFACES
(2022)
Review
Construction & Building Technology
Alexander Gladwin Alex, Amin Kedir, Tsegay Gebrehiwet Tewele
Summary: Concrete, a widely used cement-based material, has drawbacks in terms of crack resistance and tensile strength. Nanotechnology, specifically the use of graphene oxide (GO), has shown promise in enhancing the properties of cementitious materials. This review paper explores the effects of GO on the morphological and mechanical properties of cement-based materials and provides guidelines for further research.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Acoustics
Yanlong Xu, Yizhou Shen, Feng Liu, Liyun Cao, Zhichun Yang
Summary: This study investigates the flexural edge wave (FEW) on a semi-infinite isotropic elastic thin plate with a structured free edge. The dispersion relation of the modulated FEW is analytically solved by using the coupled mode theory, and the propagation characteristics of different modulated FEW modes are discussed. Numerical and experimental results demonstrate the rainbow trapping of the first-order modulated FEW and the mode conversion of the second-order modulated FEW to the bulk wave.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Acoustics
Daniele Vella, Ales Mrzel, Aljaz Drnovsek, Vasyl Shvalya, Matija Jezersek
Summary: This study reports the photoacoustic response of graphene nano-flakes and polydimethylsiloxane composite. Graphene was evenly dispersed into the polymer without the need for surface functionalization. The photoacoustic amplitude was found to be proportional to optical absorption. By embedding the freestanding film in an optical lens, high amplitude and high-frequency ultrasound with spatial confinement was achieved.
Article
Chemistry, Physical
Timur Aslyamov, Khadisha M. Zahra, Petr Zhilyaev, Alex S. Walton
Summary: Graphene nanobubbles (GNBs) have potential in nanoelectronic applications, but the synthesis methods lack control over the composition of the trapped matter. A recent study proposes a new method for producing GNBs with pure nitrogen inside on a copper substrate. The geometry of the GNBs is influenced by the van der Waals adhesion energy and elastic properties of the graphene membrane.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Xue Zhang, Xing Guo, Xiucai Sun, Zhen Su, Li Sun, Peng Wang, Yanlu Li, Fapeng Yu, Xian Zhao
Summary: This study investigated the role of oxygen in graphene growth and found that CuO and Cu2O are beneficial in promoting graphene nucleation and growth. The research provides new data for the preparation of high-quality monolayer graphene on copper substrate.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Dominika Marcin Behunova, George Gallios, Vladimir Girman, Hristo Kolev, Maria Kanuchova, Silvia Dolinska, Miroslava Vaclavikova
Summary: The study demonstrated the deposition of graphene oxide on a stainless steel substrate and its potential environmental applications. Various characterization techniques were used to assess the structure, morphology, and properties of the material, showing that the morphology and stability of the structures are related to the pre-treatment of the stainless steel substrate. This approach offers a new route for the facile fabrication of advanced electrode coatings with potential environmental applications.
Article
Chemistry, Physical
Junzhu Li, Mingguang Chen, Abdus Samad, Haocong Dong, Avijeet Ray, Junwei Zhang, Xiaochuan Jiang, Udo Schwingenschlogl, Jari Domke, Cailing Chen, Yu Han, Torsten Fritz, Rodney S. Ruoff, Bo Tian, Xixiang Zhang
Summary: This study demonstrates a method for achieving high-quality wafer-scale single-crystal graphene on sapphire substrates, which opens up new possibilities for electronic and optoelectronic applications by epitaxially growing graphene at the Cu(111)/sapphire interface and detaching the Cu film.
Article
Materials Science, Composites
Hulya Kaftelen-Odabasi, Akin Odabasi, Mustafa ozdemir, Murat Baydogan
Summary: In this study, the effect of graphene nanoplatelets (GNPs) content on electrical conductivity, flexural properties, and dynamic mechanical properties of epoxy matrix composite reinforced by carbon fibers was investigated. The results showed that an appropriate amount of GNPs can significantly improve the conductivity and storage modulus, but a high content can reduce the flexural strength.
POLYMER COMPOSITES
(2023)
Article
Engineering, Electrical & Electronic
Jun-Shuai Gong, Zhi-Liang Wang, Hui-Wen Qu, Ding-Yong Cang
Summary: This paragraph discusses the fabrication of a flexible bandpass filter based on polyimide using self-metallization technology, covering a specific frequency range of WLAN. The filter demonstrates stable performance and capability to adapt to different states.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Nanoscience & Nanotechnology
Hamza Rehman, Lena Golubewa, Alexey Basharin, Andzej Urbanovic, Erkki Lahderanta, Ekaterina Soboleva, Ieva Matulaitiene, Marija Jankunec, Yuri Svirko, Polina Kuzhir
Summary: In this study, fragmented multi-layered graphene films were synthesized directly on dielectric substrates via chemical vapor deposition (CVD) with a pre-deposited copper catalyst. The thickness of the copper film, process temperature, and growth time were found to influence the integrity, quality, and disorder of the synthesized graphene. Atomic force microscopy and Kelvin probe force microscopy measurements revealed the presence of nano-agglomerates and charge puddles on the graphene film surface. THz time domain spectroscopy measurements showed that the graphene flakes had an ac conductivity around 1200 S cm(-1) and the homogenized graphitic films had an ac conductivity of about 1000 S cm(-1). This approach provides a scalable fabrication method for graphene structures with sufficient conductivity for a wide range of THz applications.
Article
Mechanics
Youlong Chen, Xiangbiao Liao, Wei Zhao, Pengfei Yang, Hang Xiao, Yilun Liu, Xi Chen
Summary: The compressive bilayer on a soft substrate exhibits different wrinkle patterns and has a wide range of potential applications.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Multidisciplinary Sciences
C. R. Woods, P. Ares, H. Nevison-Andrews, M. J. Holwill, R. Fabregas, F. Guinea, A. K. Geim, K. S. Novoselov, N. R. Walet, L. Fumagalli
Summary: This study observes ferroelectric-like domains in hexagonal boron nitride crystals stacked at small twist angles, attributed to interfacial elastic deformations creating out-of-plane dipoles formed by pairs of boron and nitrogen atoms. This discovery opens up new possibilities for designing van der Waals heterostructures and offers an alternative probe for studying moire-superlattice electrostatic potentials.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Pierre A. Pantaleon, Tommaso Cea, Rory Brown, Niels R. Walet, Francisco Guinea
Summary: The study investigates the electronic band structures in different arrangements of graphene layers, finding narrow bands with different topology in all cases, and the strong modification of band structures by long range Coulomb interactions.
Article
Physics, Multidisciplinary
I. M. Vicent, L. Chirolli, F. Guinea
Summary: The study reveals that the interaction between graphene and a single-molecule magnet depends on the coupling between the Iron ion and the electrons in graphene, with channel selectivity leading to channel decoupling of the Kondo interaction and the formation of two almost independent Kondo systems. The development of magnetic moments and the Kondo effect is also dependent on the charge state of the graphene layer.
JOURNAL OF PHYSICS COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Miguel Goncalves, Hadi Z. Olyaei, Bruno Amorim, Rubem Mondaini, Pedro Ribeiro, Eduardo Castro
Summary: This study investigates the localization properties of electrons in incommensurate twisted bilayer graphene for small angles through numerical calculations and finds sub-ballistic states in the narrow-band region around the magic angle. These states are delocalized in momentum-space and exhibit non-Poissonian level statistics.
Article
Physics, Multidisciplinary
J. P. Santos Pires, S. M. Joao, Aires Ferreira, B. Amorim, J. M. Viana Parente Lopes
Summary: In this study, we present the first theoretical investigation on the transport properties of Weyl semimetals with point defects. We demonstrate that dilute lattice vacancies can induce modifications to the low-energy spectrum, resulting in novel transport effects.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Miguel Goncalves, Bruno Amorim, Eduardo V. Castro, Pedro Ribeiro
Summary: We find that transitions between extended and localized phases in generic 1D systems induced by quasiperiodicity are associated with hidden dualities. These spectral and eigenstate dualities can be explicitly constructed by considering commensurate approximants. The construction relies on auxiliary 2D Fermi surfaces obtained as functions of phase-twisting boundary conditions and phase-shifting real-space structure. We show that the auxiliary Fermi surface of a high-enough-order approximant converges to a universal form around the critical point of the limiting quasiperiodic system. This allows us to accurately obtain mobility edges and duality transformations for generic 1D quasiperiodic systems through their commensurate approximants.
Article
Chemistry, Multidisciplinary
Florie Mesple, Niels R. Walet, Guy Trambly de Laissardiere, Francisco Guinea, Djordje Dosenovic, Hanako Okuno, Colin Paillet, Adrien Michon, Claude Chapelier, Vincent T. Renard
Summary: The study of moire engineering has advanced with the discovery of van der Waals heterostructures, where stacking 2D layers with different lattice constants controls their electronic properties. Adjusting the twist between two graphene layers leads to new strongly-correlated-electron physics and topological effects. This study explores a novel moire superlattice in bilayer graphene under biaxial heterostrain, uncovering spiraling electronic states and atomic reconstruction. The findings suggest that biaxial heterostrain can be a valuable parameter in moire materials for further engineering advancements.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Hector Sainz-Cruz, Pierre A. Pantaleon, Vo Tien Phong, Alejandro Jimeno-Pozo, Francisco Guinea
Summary: Junctions between scanning tunneling microscope (STM) tip and superconducting twisted bilayer graphene (TBG) as well as TBG Josephson junctions (JJs) provide valuable insights into the symmetry of the superconductors' order parameter. Comparison of even and odd valley exchange superconducting phases (s-wave or f-wave) reveals that the critical current in mixed (s and f) JJs is strongly affected by the junction-lattice angle. Andreev reflection in STM-TBG junctions leads to a prominent subgap conductance peak in the case of f-wave, as observed in experiments.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
J. M. Alendouro Pinho, J. P. Santos Pires, S. M. Joao, B. Amorim, J. M. Viana Parente Lopes
Summary: This study investigates the existence of Bloch oscillations in mesoscopic devices and finds that they can be observed as a transient phenomenon in these devices.
Article
Materials Science, Multidisciplinary
J. P. Santos Pires, S. M. Joao, Aires Ferreira, B. Amorim, J. M. Viana Parente Lopes
Summary: This study analyzes the electronic structure of a cubic T-symmetric Weyl semimetal in the presence of atomic-sized vacancy defects. The results show that isolated vacancies generate nodal bound states with r(-2) asymptotic tails, even in a weakly disordered environment. These states appear as significantly enhanced nodal density of states, which reshape into a nodal peak broadened by intervacancy hybridization into a comb of satellite resonances at finite energies as the concentration of defects increases. This highlights the importance of point defects as a crucial source of elastic scattering that leads to nontrivial modifications in the electronic structure of Weyl semimetals.
Article
Materials Science, Multidisciplinary
J. C. G. Henriques, B. Amorim, R. M. Ribeiro, N. M. R. Peres
Summary: This paper discusses the optical response resulting from excitonic effect in two types of hBN bilayers: AB and AA'. By converting the four-band Bethe-Salpeter equation into a one-dimensional problem, the numerical burden of calculation is significantly reduced. The study of these bilayers is crucial for understanding twisted bilayers at arbitrary angles.
Article
Materials Science, Multidisciplinary
Hector Sainz-Cruz, Tommaso Cea, Pierre A. Pantaleon, Francisco Guinea
Summary: The study found that angle disorder has a minor impact on electron transport in twisted bilayer graphene, with barriers separating different band width regions by 50% or more leading to slight suppression of transmission, while transmission is close to 1 for normal incidence, resembling Klein tunneling.
Article
Materials Science, Multidisciplinary
Niels R. Walet, Francisco Guinea
Summary: The study investigates the effect of twisting on bilayer h-BN, including lattice relaxation and its impact on electronic structure, piezoelectric charges, and spontaneous polarization. It is found that flat bands are present even with lattice relaxation, but the spectrum becomes angle-independent for small angles. The spontaneous polarization effects are observed only in parallel alignment, suggesting a significant interlayer hopping between boron and nitrogen.
Article
Physics, Multidisciplinary
J. P. Santos Pires, B. Amorim, Aires Ferreira, Inanc Adagideli, Eduardo R. Mucciolo, J. M. Viana Parente Lopes
Summary: Rare impurity configurations play a critical role in the stability of incompressible electrons in 3D Dirac-Weyl semimetals, and strong nonperturbative effects can convert these semimetals into compressible metals. This was validated through high-resolution real-space simulations.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
J. C. G. Henriques, B. Amorim, N. M. R. Peres
Summary: This paper discusses the interaction between two negatively charged nitrogen-vacancy color centers in diamond via exciton-polaritons in a two-dimensional transition metal dichalcogenide layer. The interaction parameters are found to be highly sensitive to the distance between the centers and the transition metal dichalcogenide layer. Analytical expressions for the spectrum of the exciton-polaritons and the damping constants entering the Lindblad equation are obtained, and the conditions for exciton-mediated superradiance are discussed.
