Multi-frequency surface plasmons supported with a nanoscale non-uniform 2D electron gas formed due to a polar catastrophe at the oxide interface, dispersions, diffractions, and beyond

Abstract

Recently, 2D electron gases (2DEGs) formed at oxide interfaces are drawing increasing attention as they cause a myriad of intriguing phenomena.

Surface plasmon induced spot and line formation at interfaces of ITO coated LiNbO3 slabs and gigantic nonlinearity

“…As discussed in our earlier publications 13 , 2DEG with an electron density comparable to that of noble metals (e.g., silver and gold) can be formed at the ITO/LN interfaces through depolarization of the self-spontaneous polarization field at LN surfaces. Visible SPs are supported in the 2DEG at the interfaces via mediation of the phase gratings present in the photorefractive Fe:LN crystals.…”

“…To investigate the mechanism behind the formation of singular spots and lines at the two ITO/LN interfaces, we examined the depolarization field and electrostatic field gradient. As illustrated in 13 , the polarization field screening was confined within the nanometer range. The polarization field penetrating the screening layer was calculated and is shown in Fig.…”

“…In the recent past, interesting results have been found and reported for ITO-coated LN slabs 13 . Visible SPs can be supported in LN systems, owing to the 2D electron gas (2DEG) formed at interfaces and surfaces; however, an in-depth understanding of what occurs remains elusive in a deeper, broader sense 14 .…”

“…The nonlinear effects can be remarkably enhanced by using gratings to excite SPs 11 , 12 . To study the influence of SPs on the nonlinearity of optical materials and tailor their optical responses, indium-tin-oxide (ITO) films were deposited onto slabs of Fe-doped lithium noibate (Fe:LiNbO 3 ; Fe:LN) synthetic crystals; these are among the most investigated and commercially popular nonlinear optical materials, and they continue to attract considerable attention 13 .…”

Dramatic n-Type Doping of Monolayer Graphene with Ferroelectric LiNbO3 Crystals and Bilayer Two-Dimensional Electron Gases

“…Lithium niobate (LiNbO 3 , LN) is a common ferroelectric material, and its surface properties have attracted much attention recently . Especially, the interface polar discontinuity can cause surface atom reconstruction and charge carrier transfer to compensate the SP. − The depolarization process can accumulate 2DEGs in the nanometric scale on the surface, which is able to support visible surface plasmon polaritons (SPPs) . Recently, it has been proven theoretically and experimentally that bare LN or ITO-coated LN has a surface-metallized layer (2DEG in essence) to support visible SPPs, which leads to extremely intense energy coupling between laser beams and SPPs. − In fact, the super strong SP field can exert on the covering layer or other adsorbates.…”