Photoexcitation-Energy-Dependent Transition Pathways from a Dimer Mott Insulator to a Metal

Abstract

We theoretically study pump-photon-energy-dependent pathways of a photoinduced dimer-Mott-insulator-to-metal transition, on the basis of numerical solutions to the time-dependent Schrödinger equation for the exact many-body wave function of a two-dimensional three-quarter-filled extended Peierls-Hubbard model. When molecular degrees of freedom inside a dimer are utilized, photoexcitation can weaken the effective interaction or increase the density of photocarriers. In the organic dimer Mott insulator, $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Br, the intradimer and the interdimer charge-transfer excitations have broad bands that overlap with each other. Even in this disadvantageous situation, the photoinduced conductivity change depends largely on the pump photon energy, confirming the two pathways recently observed experimentally. The characteristic of each pathway is clarified by calculating the modulation of the effective interaction and the number of carriers involved in low-energy optical excitations. The pump-photon-energy-dependent pathways are confirmed to be realized from the finding that, although the effective interaction is always and slowly weakened, the introduction of carriers is sensitive to the pump-photon energy and proceeds much faster.

5 pages, 4 figures, accepted for publication in J. Phys. Soc. Jpn

References in corpus (5)

• Bandwidth-controlled Mott transition in $\kappa -(BEDT-TTF{)}_{2}Cu[N(CN{)}_2]B{r}_{x}C{l}_{1-x}$ I. Optical studies of localized charge excitations
• Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers
• Coupling-dependent rates of energy transfers from photoexcited Mott insulators to lattice vibrations
• Photoinduced charge and spin dynamics in strongly correlated electron systems
• Interchain coupling effects on photoinduced phase transitions between neutral and ionic phases in an extended Hubbard model with alternating potentials and an electron-lattice coupling

Cited by in corpus (7)

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• Charge Oscillations Emerging after Application of an Intense Light Field to Superconductors on a Dimer Lattice
• Photoinduced High-Frequency Charge Oscillations in Dimerized Systems
• Mechanism for Synchronization of Charge Oscillations in Dimer Lattices
• Photoinduced Pseudospin Polarization in a Three-Orbital Hubbard Model