Multivalued dispersion equation for plasmon-surface optical phonon coupling in graphene/polar substrate system
arXiv:2410.20131 · doi:10.1103/PhysRevB.110.L241403
Abstract
Dispersion equations are a common paradigm of collective excitation physics. However, in some systems, dispersion equations contain multivalued functions and their solutions are ambiguous. As an example, we consider graphene on a polar substrate where Dirac plasmons are coupled with surface optical phonons. The dispersion equation for this system contains square-root singularity. Using the initial value problem resolves this uncertainty and gives a unique solution. Particularly, we found that lower plasmon-phonon mode, which in terms of dispersion can have a good quality factor, is almost absent in excitation spectra. The physical reason and experimental evidence of the mode collapse are discussed.
6 pages, 3 figures, and supplemental material
References in corpus (18)
- The electronic properties of graphene
- Graphene plasmonics
- Fano resonances in nanoscale structures
- Dielectric function, screening, and plasmons in 2D graphene
- Theory of surface plasmons and surface-plasmon polaritons
- Dynamical polarization of graphene at finite doping
- Substrate limited electron dynamics in graphene
- Photocurrent in graphene harnessed by tunable intrinsic plasmons
- Graphene-plasmon polaritons: From fundamental properties to potential applications
- Plasmon-phonon coupling in graphene
- Plasmon-phonon Strongly-Coupled Mode in Epitaxial Graphene
- Strong phonon-plasmon coupled modes in the graphene/silicon carbide heterosystem
- Theory of Interfacial Plasmon-Phonon Scattering in Supported Graphene
- Surface polar optical phonon interaction induced many-body effects and hot-electron relaxation in graphene
- Unconventional plasmon-phonon coupling in graphene
- Semiclassical analysis of intraband collective excitations in a two-dimensional electron gas with Dirac spectrum
- Spatially dispersive dynamical response of hot carriers in doped graphene
- Logarithmic catastrophes and Stokes's phenomenon in waves at horizons