Pseudospin-orbit coupling and non-Hermitian effects in the quantum geometric tensor of a plasmonic lattice

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2024-04-25
Major/Subject
Mcode
Degree programme
Language
en
Pages
Series
Physical Review B, Volume 109
Abstract
We theoretically predict the full quantum geometric tensor, comprising the quantum metric and the Berry curvature, for a square lattice of plasmonic nanoparticles. The gold nanoparticles act as dipole or multipole antenna radiatively coupled over long distances. The photonic-plasmonic eigenfunctions and energies of the system depend on momentum and polarization (pseudospin), and their topological properties are encoded in the quantum geometric tensor. By T-matrix numerical simulations, we identify a TE-TM band splitting at the diagonals of the first Brillouin zone, that is not predicted by the empty lattice band structure nor by the highly symmetric nature of the system. Further, we find quantum metric around these regions of the reciprocal space, and even a nonzero Berry curvature despite the trivial lattice geometry and absence of magnetic field. We show that this nonzero Berry curvature arises exclusively from non-Hermitian effects, which break the time-reversal symmetry. The quantum metric, in contrast, originates from a pseudospin-orbit coupling given by the polarization and directional dependence of the radiation.
Description
Keywords
Other note
Citation
Cuerda, J, Taskinen, J M, Källman, N, Grabitz, L & Törmä, P 2024, ' Pseudospin-orbit coupling and non-Hermitian effects in the quantum geometric tensor of a plasmonic lattice ', Physical Review B, vol. 109, no. 16, 165439 . https://doi.org/10.1103/PhysRevB.109.165439