Electronic state and optical response in a hydrogen-bonded molecular conductor

Makoto Naka, Sumio Ishihara

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Motivated by recent experimental studies of hydrogen-bonded molecular conductors κ-X3(Cat-EDT-TTF)2[X=H, D], interplays of protons and correlated electrons, and their effects on magnetic, dielectric, and optical properties, are studied theoretically. We introduce a model Hamiltonian for κ-X3(Cat-EDT-TTF)2, in which molecular dimers are connected by hydrogen bonds. Ground-state phase diagram and optical conductivity spectra are examined by using the mean-field approximation and the exact diagonalization method in finite-size cluster. Three types of the competing electronic and protonic phases, charge density wave phase, polar charge-ordered phase, and antiferromagnetic dimer-Mott insulating phase are found. Observed softening of the interdimer excitation due to the electron-proton coupling implies reduction of the effective electron-electron repulsion, i.e., "Hubbard U," due to the quantum proton motion. Contrastingly, the intradimer charge excitation is hardened due to the proton-electron coupling. Implications of the theoretical calculations to the recent experimental results in κ-X3(Cat-EDT-TTF)2 are discussed.

Original languageEnglish
Article number245110
JournalPhysical Review B
Volume97
Issue number24
DOIs
Publication statusPublished - 2018 Jun 7

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Electronic states
Hydrogen
conductors
Protons
cats
Electrons
hydrogen
electronics
protons
electrons
Dimers
dimers
Optical conductivity
Hamiltonians
Charge density waves
softening
Dielectric properties
Ground state
excitation
Phase diagrams

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Electronic state and optical response in a hydrogen-bonded molecular conductor. / Naka, Makoto; Ishihara, Sumio.

In: Physical Review B, Vol. 97, No. 24, 245110, 07.06.2018.

Research output: Contribution to journalArticle

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