Plasmonic excitations in two-dimensional materials: effects of structural symmetry and material anisotropy

Plasmonics in two-dimensional materials, an emerging direction of nano-optics, has attracted great attention recently, which exhibits unique properties than that in noble metals. Extending its advanced features by different manipulations is very beneficial for its promotion. In this paper, we study plasmonic excitations in graphene and black phosphorus (BP) nanostructures, where the effects of structural symmetry and material anisotropy are discussed. We show that the two factors are crucial to mode excitations, e.g. the extinction can be dominated by higher order modes rather than dipole resonance. The behavior occurs only in the direction hosting larger resonance frequencies, e.g. armchair (AC) direction of BP and shorter side of graphene rectangles. In BP rectangles along AC direction, the two factors are competing, and thus can be applied cooperatively to tune plasmonic resonance, from dipole to higher order excitations. Besides, the manipulation can also be achieved by designing BP square rings, in which the interaction between outer and inner edges show great impact on mode excitations. Our studies further promote the understanding of plasmonics in two-dimensional materials, and will pave the way for particular plasmonic applications.

Strong coupling in two-dimensional materials-based nanostructures: a review

Strong interaction between electromagnetic radiation and matter leads to the formation of hybrid light-matter states, making the absorption and emission behavior different from those of the uncoupled states. Strong coupling effect results in the famous Rabi splitting and the emergence of new polaritonic eigenmodes, exhibiting spectral anticrossing behavior and unique energy-transfer properties. In recent years, there has been a rapidly increasing number of works focusing on strong coupling between nanostructures and two-dimensional materials (2DMs), because of the exceptional properties and applications they demonstrate. Here, we review the significant recent advances and important developments of strong light-matter interactions in 2DMs-based nanostructures. We adopt the coupled oscillator model to describe the strong coupling and give an overview of various hybrid nanostructures to realize this regime, including graphene-based nanostructures, black phosphorus-based nanostructures, transition-metal dichalcogenides-based nanostructures, etc. In addition, we discuss potential applications that can benefit from these effects and conclude our review with a perspective on the future of this rapidly emerging field.

Progress in Foldcore Sandwich Manufacturing and Application

The sandwich structure with foldcore is a new type of structural material with light weight, high specific strength, high specific rigidity and multi-functional potential, which is connected with each other in core space, this kind of three dimensional structures can be formed by folding based on two dimensional materials. The main research achievements and characteristics of sandwich structure with foldcore in recent years are summarized and analyzed according to the lightweight and multi-functional requirements of aircraft structure in this paper. The configuration optimization scheme and fabrication process of the sandwich structure with foldcore are described. Moreover, the research status of multi-function of the sandwich structure with foldcore are summarized, including sound insulation, thermal protection, stealth performance of the structure, etc.

The Research on the Complexity of 1T-TaS2 at Ultra-low Temperatures

Graphene, as a successfully industrialized two-dimensional material, has greatly promoted the development of other two-dimensional materials, such as transition metal dichalcogenide (TMDs). 1T-TaS2 is a classical TMDs material, which presents metallicity at high temperature. It undergoes a variety of charge density wave (CDW) phase transitions during the temperature declining process, and presents insulating properties at low temperature. During the temperature rise period, 1T-TaS2 goes through a phase transition, from an energy band insulator to Mott insulator, followed by an insulation-metal phase transition. The complexity of 1T-TaS2 phase diagram encourages researchers to conduct extensive research on it. This paper, via means of resistance, magnetic susceptibility and other technical methods, finds out that the ultra-low temperature of 1T-TaS2 suggests additional complexity. In addition, with the angle resolved photoemission spectroscopy (ARPES) technique of in-situ alkali metal evaporation, this paper proposes that the 1T-TaS2 ultra-low temperature ground state may exist a combination of state and surface state. Our findings provide more experimental evidence for the physical mechanism of this system.