A state-of-the-art variational wave function incorporating Jastrow-type exciton-phonon correlations, the global-local Ansatz, is utilized to elucidate exciton-phonon correlations in a generalized form of the Holstein Hamiltonian with the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. Much lowered ground-state energies are found for the global-local Ansatz when compared with the previously studied Toyozawa Ansatz. A three-dimensional phase diagram spanned by the transfer integral and two forms of exciton-phonon coupling is given to illustrate polaronic self-trapping near the zone center.

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An improved variational approach to off-diagonal exciton-phonon coupling.

A variational approach is employed to compute the wave function of a single polaron for a two-dimensional Holstein Hamiltonian with arbitrary forms of linear particle–boson interactions and boson dispersion relations. The Toyozawa ansatz is utilized, and generalizations to multiple polarons are outlined. Applications are made to model superradiance in pseudoisocyanine bromide J-aggregates, and to calculate quasiparticle dispersion of an itinerant hole in a two-dimensional antiferromagnet.

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Lattice and spin polarons in two dimensions

Two-photon absorption and two-exciton polaron structure in molecular aggregates

Single-polaron properties in the one-dimensional Holstein and SSH models

http://www.cell.com/article/S2405844022001852/pdf

Fumio Sasaki

Papers

Exciton polarons in molecular aggregates: a dynamical coherent potential approximation approach