Band structure engineered layered metals for low-loss plasmonics

Abstract

Plasmonics currently faces the problem of seemingly inevitable optical losses occurring in the metallic components that challenges the implementation of essentially any application. In this work, we show that Ohmic losses are reduced in certain layered metals, such as the transition metal dichalcogenide TaS2, due to an extraordinarily small density of states for scattering in the near-IR originating from their special electronic band structure. On the basis of this observation, we propose a new class of band structure engineered van der Waals layered metals composed of hexagonal transition metal chalcogenide-halide layers with greatly suppressed intrinsic losses. Using first-principles calculations, we show that the suppression of optical losses lead to improved performance for thin-film waveguiding and transformation optics.

Electron–phonon interaction and transport properties of metallic bulk and monolayer transition metal dichalcogenide TaS 2

“…This can change e.g. optical properties and was discussed in an previous study by us 7 . However, due to the metallic character of TaS 2 and the energetic distance of the lower p-like band to E F , these changes do not alter the electronic transport results.…”

“…Cu or Pb. These material properties, together with a high optical transmittance in the visible range, enables H-TaS 2 to be a promising system for application as a transparent conducting oxide 7 .…”

“…We note, that µ ⊥ > µ || can be achieved for −1.5 eV < E − E F < −0.3 eV, which originates largely from p-orbitals forming highly dispersive bands with high out-of-plane velocities. As mentioned before and shown in the supplemental material, applying GW or hybrid functional calculations, these bands will be shifted downwards in energy by about 0.6 eV, making them unlikely to accessed by hole doping 7,8 . As noted earlier, with regard to potential application as transparent conductive electrodes, the electrical sheet conductance should be the material property in focus and is shown in Fig.…”

“…MoS 2 and WS 2 , have been extensively in focus for their promising electronic mobilities and thus a high potential in thin-film transistor applications [3][4][5] . Recently metallic TMDs are in focus for their potential as transparent conductive electrodes and gained increasing importance for information-, optoelectronic-and energy-applications 6,7 . Crucial requirements for these are high electrical conductivity and high transparency; properties that are often contradicting.…”

Nonlocal plasmonic response of doped and optically pumped graphene, MoS2 , and black phosphorus

“…Transition metal dichalcogenides such as MoS 2 possess excellent electronic and optical properties [2,3], in particular with regard to the Purcell effect and metamaterial design [4,5], while black phosphorus (BP) offers a wide tunable band gap, high carrier mobility, and large in-plane anisotropy. [6,7].…”