By combining a hexagon and square carbon ring, a series of two-dimensional (2D) carbon allotropes, named (HS)-graphene, can be obtained. Based on the first-principles calculations, the energetic, dynamical and mechanical stability were evaluated. Importantly, we predicted that some carbon allotropes possess the Dirac cone structure. A pair of Dirac points can be found for (HS)-graphene and (HS)-graphene in the first Brillouin zone. With varying the number of four- and six-membered rings, a distorted Dirac cone can be observed for (HS)-graphene and (HS)-graphene. To get insight into the features of the Dirac cone, the orbital decomposed band structure, the corresponding density of states, the projection map of the three-dimensional bands and Fermi velocity were investigated. Interestingly, the Fermi velocity of (HS)-graphene is up to 8.8 × 10 m s along the direction, which is higher than that of graphene, indicating higher potential application in electronic transport. Finally, we discuss the mechanical properties of (HS)-graphene. Our work provides a new way to design the stable 2D carbon allotropes with a Dirac cone.
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http://dx.doi.org/10.1039/d3cp01293j | DOI Listing |
Adv Sci (Weinh)
January 2025
Department of Physics, Chung-Ang University, Seoul, 06974, Republic of Korea.
The fundamental characteristics of collective interactions in topological band structures can be revealed by the exploration of charge screening in topological materials. In particular, distinct anisotropic screening behaviors are predicted to occur in Dirac nodal line semimetals (DNLSMs) due to their peculiar anisotropic low-energy dispersion. Despite the recent extensive theoretical research, experimental observations of exotic charge screening in DNLSMs remain elusive, which is partly attributed to the coexisting trivial bands near the Fermi energy.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory of Structural Analysis for Industrial Equipment & School of Physics, Dalian University of Technology, Dalian 116024 People's Republic of China.
ACS Omega
December 2024
Faculty UnB Planaltina, Materials Science Postgraduate Program, University of Brasília, Brasília, Federal District 73345-010, Brazil.
Two-dimensional (2D) silicon-based materials have garnered significant attention for their promising properties, making them suitable for various advanced technological applications. Here, we present Irida-Silicene (ISi), a novel 2D silicon allotrope inspired by Irida-Graphene (IG), which was recently proposed and is entirely composed of carbon atoms. ISi exhibits a buckled structure composed of 3-6-8 membered rings, unlike its planar carbon counterpart.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA and Quantum Materials and Sensing Institute, Northeastern University, Burlington, Massachusetts 01803, USA.
In contrast to the Dirac-cone materials in which the low-energy spectrum features a pseudospin-1/2 structure, Lieb and Dice lattices both host triply degenerate low-energy excitations. Here, we discuss moiré structures involving twisted bilayers of these lattices, which are shown to exhibit a tunable number of isolated flat bands near the Fermi level due to the bipartite nature of their structures. These flat bands remain isolated from the high-energy bands even in the presence of small higher-order terms and chiral-symmetry-breaking interlayer tunneling.
View Article and Find Full Text PDFNanoscale
December 2024
University of Brasília, Institute of Physics, Brasília, Federal District, Brazil.
The recent synthesis of nitrogen-doped amorphous monolayer carbon (NAMC) opens new possibilities for multifunctional materials. In this study, we have investigated the nitrogen doping limits and their effects on NAMC's structural and electronic properties using density functional-based tight-binding simulations. Our results show that NAMC remains stable up to 35% nitrogen doping, beyond which the lattice becomes unstable.
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