Article
Materials Science, Multidisciplinary
Ahmal Jawad Zafar, Aranyo Mitra, Vadym Apalkov
Summary: In this study, the electron dynamics of a graphene nanoring in the presence of an ultrashort optical pulse were theoretically investigated. It was found that circularly polarized pulses can induce valley polarization in the graphene nanoring, whereas no valley polarization is observed in a graphene monolayer. The magnitude of the valley polarization in the graphene nanoring depends on the system parameters.
Article
Multidisciplinary Sciences
A. Poszwa
Summary: This theoretical investigation focuses on the electron transport properties of rectangular graphene quantum dots (GQDs) with non-centro-symmetric out-of-plane Gaussian deformation of elliptic type. Different levels of deformation are explored to determine the optimal geometry for potential electronic applications. The electronic properties of deformed GQDs are analyzed in terms of local density of states (LDOS), band-gap opening, and equilibrium ballistic conductance. The relationship between the symmetry of the LDOS structure and the properly defined local strain field (LSF) map is studied and confirms predictions made using the concept of a pseudomagnetic field in continuum models of graphene.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Multidisciplinary
Emma L. Minarelli, Jonas B. Rigo, Andrew K. Mitchell
Summary: This article investigates a graphene-based two-channel charge-Kondo device and uncovers a rich phase diagram. It finds that the strong coupling pseudogap Kondo phase persists in the channel-asymmetric case. Furthermore, despite the vanishing density of states in the graphene leads, a finite linear conductance is observed at the frustrated critical point.
Article
Materials Science, Multidisciplinary
Ankan Mukherjee, Bhaskaran Muralidharan
Summary: Recent experiments on current blockades in 2D material quantum-dot platforms have provided new opportunities for spin and valley-qubit processing. In this study, we propose a model to simulate the Pauli blockades in a double quantum dot structure, taking into account the interplay of Coulomb interactions, inter-dot tunneling, Zeeman splittings, and intrinsic spin-orbit coupling. We show that the conducting and blocking states responsible for the blockades cannot be explained solely by spin or valley pseudo-spins, but are a result of the coupled effect of all degrees of freedom. We also numerically predict the occurrence of Pauli blockades and verify our model with experimental data, suggesting its potential application in machine learning algorithms.
Article
Chemistry, Multidisciplinary
Yang Zhang, Yuning Li, Qing You, Jingye Sun, Ke Li, Hao Hong, Lingbing Kong, Mingqiang Zhu, Tao Deng, Zewen Liu
Summary: In this paper, a 3D photodetector based on a graphene-SWCNT heterojunction is fabricated using a self-rolled-up process. The 3D microcavity structure enhances the optical field and improves the photoresponsivity compared to 2D devices. The photodetector demonstrates broadband photodetection, fast photoresponse speed, excellent sensitivity, mid-infrared detection, and room-temperature imaging capability. This 3D heterojunction photodetector provides a feasible pathway for high-performance graphene-based photodetectors and can be integrated with other light absorptive materials.
Article
Physics, Multidisciplinary
Angelika Knothe, Leonid Glazman, Vladimir Fal'ko
Summary: This study investigates quantum tunnelling transport across few-electron bilayer graphene quantum dots and determines the orbital, spin, and valley composition of single- and two-electron dot states using differential conductance. The findings elucidate spin- and valley-dependent tunnelling mechanisms, providing insights for the utilization of bilayer graphene quantum dots as spin and valley qubits.
NEW JOURNAL OF PHYSICS
(2022)
Article
Chemistry, Physical
G. Nagaraj, Mustafa K. A. Mohammed, Masoud Shekargoftar, P. Sasikumar, P. Sakthivel, G. Ravi, M. Dehghanipour, Seckin Akin, Ahmed Esmail Shalan
Summary: This study introduces a method of using graphene quantum dots to modify the SnO2/ZnO layer to enhance the performance of perovskite solar cells, significantly improving opto-electronic properties and increasing power conversion efficiency. Devices with the modified electron transport layer show higher open-circuit voltage and long-term stability.
MATERIALS TODAY ENERGY
(2021)
Review
Energy & Fuels
Norazuwana Shaari, Siti Kartom Kamarudin, Raihana Bahru
Summary: Carbon quantum dots (CQDs) and graphene quantum dots (GQDs) are frequently mentioned in recent studies for their unique potential in electrical, optical, and optoelectrical properties. They are highly stable due to their carbon material and environmentally friendly nature. Various production methods and additive materials can enhance their performance, with shapes and sizes influenced by different parameters. Applications in fuel cell technology have shown improved performance.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
Fionnuala Solomon, Stephen R. Power
Summary: Intrinsic and extrinsic valley Hall effects are predicted to emerge in graphene systems, with strong valley-dependent scattering observed in bilayer graphene quantum dots. Custom mass profiles in bilayer graphene devices provide an excellent platform for future exploration of valleytronic phenomena in two-dimensional materials.
Article
Chemistry, Multidisciplinary
Wei Fu, Jiefu Yin, Huaqiang Cao, Zhongfu Zhou, Junying Zhang, Jingjing Fu, Jamie H. Warner, Cheng Wang, Xiaofang Jia, G. Neville Greaves, Anthony K. Cheetham
Summary: The photoluminescence blinking behavior of single quantum dots under steady illumination is a significant yet controversial topic. It hinders the use of single quantum dots in bioimaging. Different mechanisms, particularly the non-radiative Auger recombination mechanism, have been proposed to explain it. Fluorescence non-blinking is observed in photocharged single graphene quantum dots (GQDs) due to the presence of singly charged trions that maintain photon emission through radiative and non-radiative Auger recombination. This phenomenon is attributed to the different energy levels caused by oxygen-containing functional groups in the GQDs, and the suppression of blinking is attributed to trap site filling caused by Coulomb blockade.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Ceramics
Chaoqun Lu, Weijia Zhang, Zhaoyi Jiang, Yulong Zhang, Cong Ni
Summary: Introducing graphene quantum dots into SnO2 improved film morphology, reduced surface roughness, and increased efficiency of perovskite photovoltaic devices.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Chao Liu, Qing Yin, Wenbo Zhang, Yan Bao, Peipei Li, Lifen Hao, Jianzhong Ma
Summary: By depositing ionic liquids and carbon quantum dots on the surface of graphene, the tribological properties of polymer composites can be improved, leading to a decrease in friction coefficient and volume wear rate of BMI materials.
Article
Energy & Fuels
T. Archana, S. Sreelekshmi, G. Subashini, A. Nirmala Grace, M. Arivanandhan, R. Jayavel
Summary: The study investigated the use of graphene quantum dots as a passivating layer for cadmium sulfide quantum dot-sensitized solar cells, which significantly enhanced the photoconversion efficiency of the QDSSCs.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Green & Sustainable Science & Technology
Savisha Mahalingam, Abreeza Manap, Azimah Omar, Foo Wah Low, N. F. Afandi, Chin Hua Chia, Nasrudin Abd Rahim
Summary: Graphene quantum dots (GQDs) with outstanding properties can be chemically modified and functionalized for high-performance dye-sensitized solar cells. Optimizing electron transport and electrolyte can further enhance the efficiency of GQD-DSSC.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Review
Chemistry, Multidisciplinary
Sajid Ali Ansari
Summary: This review discusses the utilization of graphene quantum dots (GQDs) and their composites in energy storage devices. The high conductivity, abundant specific surface area, and sufficient solubility of GQDs make them suitable for a wide range of applications such as optical, catalysis, energy storage, and conversion. The article also addresses the challenges and provides future perspectives for implementing GQDs in energy storage research.
Article
Chemistry, Physical
J. D. Correa, M. Pacheco, Sergio Bravo, Leonor Chico
Article
Multidisciplinary Sciences
A. Gonzalez I., M. Pacheco, A. M. Calle, E. C. Siqueira, P. A. Orellana
Summary: This article studies the influence of quantum interference effects on electronic transport through a parallel triple quantum-dot system coupled to normal and superconducting leads in the linear response and non-equilibrium regime. Using a triple impurity Anderson Hamiltonian with Coulomb intra-dot correlations in all quantum dots, the Andreev conductance and transmittance are calculated within the superconductor gap. The results show Fano and Dicke-like resonances in the Andreev reflection spectra, with abrupt changes in charge due to the Dicke effect being one of the main findings.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Applied
D. Zambrano, P. A. Orellana, L. Rosales, A. Latge
Summary: This work investigates the spin and valley transport properties of a WSe2 monolayer on a ferromagnetic insulator, focusing on controlling the properties through external potentials. By considering single- and double-barrier structures with gate potentials, the study analyzes the efficiency of polarized transport with respect to gate potentials and geometrical configurations. Additionally, modulation of spin and valley polarizations is achieved by applying an ac potential, especially in the terahertz range, suggesting potential applications in spin- and valley-dependent transport within an optimal geometrical parameter regime.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Applied
G. Buchs, M. Marganska, J. W. Gonzalez, K. Eimre, C. A. Pignedoli, D. Passerone, A. Ayuela, O. Groning, D. Bercioux
Summary: The study demonstrates that breaking various symmetries in metallic nanotube quantum dots of arbitrary chirality strongly relaxes the selection rules in the electric dipole approximation, leading to a richer set of allowed optical transitions spanning frequencies from 1 THz to several tens of THz. This may offer a promising platform to design tunable terahertz detectors that could operate at liquid nitrogen temperatures, with a range of operating regimes from high-resolution gate-tunable terahertz sensors to broadband terahertz detectors largely unaffected by temperatures up to 100 K.
APPLIED PHYSICS REVIEWS
(2021)
Article
Physics, Multidisciplinary
Fabian Medina, Juan Pablo Ramos-Andrade, Luis Rosales, Pedro Orellana
Summary: The study investigates the spectra in an Aharonov-Bohm quantum-ring interferometer forming a Josephson junction between two topological superconductor nanowires. Different patterns of spectra are observed depending on the size of the quantum ring and the coupling, including line, point, undulated nodes, and flat bands. These patterns could potentially be detected by persistent and Josephson currents, providing insights into the behavior of current signals.
ANNALEN DER PHYSIK
(2021)
Article
Physics, Condensed Matter
J. W. Gonzalez
Summary: The application of strain allows for manipulation of the properties of 2D materials. By taking advantage of the reversible semiconductor-metal transition observed in certain monolayers, a hetero-bilayer device is proposed. The calculations show that reversible control can be achieved in specific layers depending on the direction of applied strain.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
Fabian Gonzalo Medina, Dunkan Martinez, Alvaro Diaz-Fernandez, Francisco Dominguez-Adame, Luis Rosales, Pedro A. Orellana
Summary: This article presents a realistic setting for assessing the existence of Majorana zero modes by considering a quantum ring with Rashba spin-orbit coupling and threaded by a magnetic flux, in contact with a topological superconducting nanowire. The results show that the Rashba spin-orbit coupling allows for tuning the position of zero energy crossings and has significant effects on spin-polarized persistent currents.
SCIENTIFIC REPORTS
(2022)
Article
Biochemistry & Molecular Biology
Mireya Santander-Nelli, Bastian Boza, Felipe Salas, David Zambrano, Luis Rosales, Paulina Dreyse
Summary: A series of new Ir(III) complexes have been designed as luminescent materials by using a mixture of different ligands. The emitting properties of these complexes have been analyzed theoretically to determine the optimal emission colors. A system using a combination of these complexes has been proposed to produce white luminescent materials.
Article
Chemistry, Multidisciplinary
Antonio Bernardo Felix, Monica Pacheco, Pedro Orellana, Andrea Latge
Summary: Graphene/fullerene heterostructures have unique transport properties, making them suitable for electronic devices. By controlling the coupling of nanoribbons and carbon nanotubes, charge filtering and tuned transport can be achieved. In addition, specific edge structures can result in midgap states and differential negative resistance.
Article
Physics, Multidisciplinary
K. A. Gonzalez, C. D. Nunez, P. A. Orellana, L. Rosales
Summary: In this study, the thermoelectrical properties of a silicene nanoribbon heterostructure with a central fully doped conductor and two pristine leads were investigated. Using a tight-binding Hamiltonian, the thermoelectric properties of the system were calculated as a function of confinement and external field. The results showed an enhancement of thermopower in the presence of a transverse electric field and a violation of the Wiedemann-Franz law near the ad-atom energy. These findings indicate that the thermoelectric properties of doped silicene nanoribbons can be efficiently controlled with external perturbations.
FRONTIERS IN PHYSICS
(2023)
Article
Chemistry, Physical
Sergio Bravo, M. Pacheco, J. D. Correa, Leonor Chico
Summary: This study analyzes the electronic structure of monolayer pentagonal palladium diselenide (PdSe2) from the perspective of topological band theory. The low-lying conduction bands are found to be topologically nontrivial and protected by time reversal and crystalline symmetries. Numerical evidence supporting the nontrivial nature of these bands is provided. Furthermore, relevant physical responses, such as spin Hall conductivity, are obtained from the topological viewpoint.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Carlos Rojas, A. Leon, M. Pacheco, Leonor Chico, P. A. Orellana
Summary: In this study, we investigate the electronic transport through an all-carbon quantum ring side-coupled to a quantum wire using both first-principles calculations and a tight-binding approach. We find that the conductance and density of states can be derived analytically for two different bond configurations: cumulenic ring and polyynic ring. For the cumulenic ring, we observe an antiresonant peak in the conductance at the Fermi level when the number of carbon atoms in the ring is a multiple of four. However, this effect disappears for the polyynic configuration where the hoppings in the carbon rings are alternating. Additionally, a gap opens at the Fermi energy in the polyynic rings, leading to distinct transport signatures. The changes in conductance due to the carbon ring are consistent with the results of first-principles calculations, suggesting that transport measurements can be used to understand the bonding characteristics of these novel carbon nanostructures.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Sergio Bravo, M. Pacheco, V. Nunez, J. D. Correa, Leonor Chico
Summary: Theoretical study on the electronic and optical properties of pentagonal materials derived from Cairo tiling, with a focus on their symmetry-based features. Results show that pentagonal structures can exist in chiral and achiral lattices with specific high-symmetry points and nodal lines. Linear and nonlinear optical characteristics were calculated, showing enhancement in shift current due to nodal lines and points, hinting at potential applications.
Correction
Physics, Multidisciplinary
Ana M. Calle, Monica Pacheco, Pedro A. Orellana, Jorge A. Otalora
ANNALEN DER PHYSIK
(2020)
