Hyperbolic Cooper-Pair Polaritons in Planar Graphene/Cuprate Plasmonic Cavities

Abstract

Hyperbolic Cooper-pair polaritons (HCP) in cuprate superconductors are of fundamental interest due to their potential for providing insights into the nature of unconventional superconductivity. Here, we critically assess an experimental approach using near-field imaging to probe HCP in Bi 2 Sr 2 CaCu 2 O 8+x (Bi-2212) in the presence of graphene surface plasmon polaritons (SPP). Our simulations show that inherently weak HCP features in the near-field can be strongly enhanced when coupled to graphene SPP in layered graphene/hexagonal boron nitride (hBN)/Bi-2212 heterostructures. This enhancement arises from our multilayered structures effectively acting as plasmonic cavities capable of altering collective modes of a layered superconductor by modifying its electromagnetic environment. The degree of enhancement can be selectively controlled by tuning the insulating spacer thickness with atomic precision. Finally, we verify the expected renormalization of room-temperature graphene SPP using near-field infrared imaging. Our modeling, augmented with data, attests to the validity of our approach for probing HCP modes in cuprate superconductors.

Mesoscopic electrodynamics at metal surfaces

“…As we shall see in the next subsection, this can even be extended to new explorations of atomic-scale properties beyond the jellium picture of metals. Finally, the use of graphene as a probe of nearby electrodynamics was recently even suggested as a possible avenue for explorations beyond the common metallic state in a correlated matter [359][360][361].…”

Tunable Planar Focusing Based on Hyperbolic Phonon Polaritons in α‐MoO3

“…The roadmap for polaritons has been dramatically enriched by the emergence of van der Waals (vdW) materials that are attracting substantial research attention because of their potential photonic and optoelectronic applications. [ 8 ] These vdW materials support various types of surface modes, including plasmon polaritons involving the collective motion of charge carriers in conductors, [ 5a,6d,9 ] atomic vibrations (phonons) in polar insulators, [ 10 ] excitons in semiconductors, [ 11 ] cooper pairs in superconductors, [ 12 ] and spin resonances in (anti‐)ferromagnets. [ 13 ] Among them, phonon polaritons (PhPs) feature ultra‐low inelastic losses, highly confined light fields, and strong stability at room temperature.…”

Long-Lived Phonon Polaritons in Hyperbolic Materials

“…In this setup, the incident light with IR frequency  is focused onto the metallized tip of an atomic force microscope (AFM). As the tip approaches the sample, a concentrated evanescent field excites polaritonic modes with a ( ) that is much shorter than the free-space wavelength IR = 2π / of the incident photons [22][23][24][25][26] . This unique nano-IR apparatus has been routinely employed in studies of plasmon and phonon polaritons as well as for visualizing inhomogeneities in complex oxides [19][20][21] .…”