Researchers from Italian Institute of Technology revealed 3D Dirac plasmons in a bulk material that could enable novel electronic nano devices
A plasmon is a quantum of plasma oscillation similar to an optical oscillation of photons in light. Plasmons are collective oscillations of the free electron gas density found in conventional metals and semiconductors. These condensed matter particles are gaining interest for applications in sensing, fast electronics, and solar cell technology. Plasmons can also exist in exotic solids known as Dirac materials made from particles such as fermion, d-wave superconductors, graphene, and topological insulators.
Dirac plasmons have several advantages such as a higher propagation velocity and frequency tenability as compared to conventional plasmons. Dirac plasmons have so far been observed in 2D materials such as graphene. However, 2D plasmons are susceptible to presence of defects and contaminants on the surface of a material. Now, researchers at the Graphene Labs of Italian Institute of Technology, in Genoa, provided direct evidence of 3D Dirac plasmons in the bulk of platinum ditelluride (PtTe2).
Recent research revealed Dirac properties in PtTe2 and suggested that it is a 3D type-II Dirac semimetal. The electronic excitation of the material was characterized with high-resolution electron-energy-loss spectroscopy and the data was interpreted by comparing them with density-functional-theory predictions. The researchers observed electronic quasiparticles that were collectively moving in energy bands with the anisotropic tilted cones characteristic of a type-II Dirac semimetal. This in turn suggested that these quasiparticles are 3D Dirac plasmons. The strength of these 3D plasmons could be used to create plasmon-based nanodevices such as photodetectors. According to the researchers such devices could be built using thin PtTe2 layers as the material is easily cleaved. Moreover, the findings revealed that the plasmons could be excited with an energy of around 0.5 Ev that corresponds to a wavelength of around 2.4 μm. Such feature could enable optoelectronic applications where plasmons are controlled with near-infrared laser light. The research was published in the journal Physical Review Letters on August 22, 2018.