Photoproduction of spin and charge carriers in halogen-bridged binuclear platinum chain complexes

Abstract

Nonlinear lattice relaxation of photoexcited diplatinum-halide chain compounds is theoretically investigated within a one-dimensional extended Peierls-Hubbard model. We first illuminate the whole relaxation scenario in terms of variational wave functions and then visualize each relaxation channel numerically integrating the Schrödinger equation. High-energy excitations above the electron-hole continuum tend to relax into polarons, while excitons pumped within the optical gap, unless luminescent, turn into solitonic states nonradiatively. Neutral and charged solitons coexist as stable photoproducts, which has never been observed in conventional platinum-halide chains, and they are highly resonant on the occasion of their birth and geminate recombination.

Photoinduced Structural Phase Transitions in Polyacene

“…Since a valley precedes the barrier, Coulomb interactions stimulate the Frank-Condon state to relax and accelerate its localization. 48 We are thus convinced of the ultrafast quasifemtosecond self-localization of photogenerated charge-transfer excitons in the correlated dynamics (Figs. [10][11][12][13][14] and its slowing down in the uncorrelated dynamics ( Figs.…”

“…Figure 11, demonstrating geminate recombinations of domain walls in the early stage, implies that correlated electrons encounter energy barriers on the way of photogenerated excitons being self-trapped and further dissociated into distant kinks and antikinks. A correlation-induced energy barrier on the relaxation path to far distant domain walls is observed in platinum-halide chain compounds as well, 46,48,54,55 which are well known to be photoactive Peierls insulators. Since a valley precedes the barrier, Coulomb interactions stimulate the Frank-Condon state to relax and accelerate its localization.…”

“…The phase transition originates in generation of kink and antikink in pairs. Within the SSH modeling, neither spin nor charge accompanies any kink as a result of resonating nonlinear excitations, 48,56 where neutral and charged kinks are isoenergetic. With increasing Coulomb interactions, their degeneracy is lifted and those with excess spin (charge) density in their centers are relatively stabilized (destabilized).…”

Photocontrollable Mixed-Valent States in Platinum-Halide Ladder Compounds

“…The similar methods are applied to electron-spin coupled systems [40] as well, where local spins coupled with conducting electrons are treated classically. We initially add small random values to the lattice displacements as thermal fluctuations, which are three orders of magnitude smaller than the initial lattice displacements [41]. Hereafter, the total number of units N is set equal to 64, unless otherwise noticed.…”

Photorefinement of the Mixed Ground State of a Platinum-Iodide Nanotubular Assembly

“…Discretizing the time by ∆t, we perform the integration of the Newtonian equations step by step. In the time-evolutional calculations, we initially add random values to the lattice distortions as thermal fluctuations, which are three orders of magnitude smaller than the initial lattice displacements [16]. We set N = 50 and…”