### Abstract

In this, the last of three articles on the optical absorption of electrons in a half-filled Peierls-distorted chain, we address the dimerized extended Hubbard model in the limit of a large on-site interaction U. When the Hubbard interaction is large compared with both the bandwidth W and the nearest-neighbour interaction V, the charge dynamics are property described by the Harris-Lange model. This model can be exactly mapped onto a model of Tree spinless fermions in parallel (Hubbard) bands of width W which are eventually Peierls split. To determine the coherent absorption features at low temperatures, we design and employ the 'no-recoil approximation' in which we assume that the momentum transfer to the spin degrees of freedom can only be Δq_{s} = 0 or Δq_{s} = π/a during an optical excitation We present explicit analytical results for the optical absorption in the presence of a lattice dimerization δ and a nearest-neighbour interaction V for the Néel and dimer state We find that the coherent part of the optical absorption for V = 0 is given by a single peak at ω = U and broad but weak absorption bands for Wδ≤|ω - U|≤W. The central peak at ω = U vanishes only for δ = 0 in the Néel state. For an appreciable nearest-neighbour interaction V > W/2, almost all spectral weight is transferred to the Δq_{c} = 0 exciton and the Δq_{c} = π/a exciton, whose relative spectral weights depend very sensitively on both the lattice and the spin dimerization of the ground state.

Original language | English (US) |
---|---|

Pages (from-to) | 47-65 |

Number of pages | 19 |

Journal | Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties |

Volume | 75 |

Issue number | 1 |

State | Published - Jan 1997 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Chemical Engineering(all)
- Physics and Astronomy(all)

### Cite this

*Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties*,

*75*(1), 47-65.

**Optical absorption of strongly correlated half-filled Mott-Hubbard chains.** / Gebhard, F.; Bott, K.; Scheidler, M.; Thomas, P.; Koch, Stephan W.

Research output: Contribution to journal › Article

*Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties*, vol. 75, no. 1, pp. 47-65.

}

TY - JOUR

T1 - Optical absorption of strongly correlated half-filled Mott-Hubbard chains

AU - Gebhard, F.

AU - Bott, K.

AU - Scheidler, M.

AU - Thomas, P.

AU - Koch, Stephan W

PY - 1997/1

Y1 - 1997/1

N2 - In this, the last of three articles on the optical absorption of electrons in a half-filled Peierls-distorted chain, we address the dimerized extended Hubbard model in the limit of a large on-site interaction U. When the Hubbard interaction is large compared with both the bandwidth W and the nearest-neighbour interaction V, the charge dynamics are property described by the Harris-Lange model. This model can be exactly mapped onto a model of Tree spinless fermions in parallel (Hubbard) bands of width W which are eventually Peierls split. To determine the coherent absorption features at low temperatures, we design and employ the 'no-recoil approximation' in which we assume that the momentum transfer to the spin degrees of freedom can only be Δqs = 0 or Δqs = π/a during an optical excitation We present explicit analytical results for the optical absorption in the presence of a lattice dimerization δ and a nearest-neighbour interaction V for the Néel and dimer state We find that the coherent part of the optical absorption for V = 0 is given by a single peak at ω = U and broad but weak absorption bands for Wδ≤|ω - U|≤W. The central peak at ω = U vanishes only for δ = 0 in the Néel state. For an appreciable nearest-neighbour interaction V > W/2, almost all spectral weight is transferred to the Δqc = 0 exciton and the Δqc = π/a exciton, whose relative spectral weights depend very sensitively on both the lattice and the spin dimerization of the ground state.

AB - In this, the last of three articles on the optical absorption of electrons in a half-filled Peierls-distorted chain, we address the dimerized extended Hubbard model in the limit of a large on-site interaction U. When the Hubbard interaction is large compared with both the bandwidth W and the nearest-neighbour interaction V, the charge dynamics are property described by the Harris-Lange model. This model can be exactly mapped onto a model of Tree spinless fermions in parallel (Hubbard) bands of width W which are eventually Peierls split. To determine the coherent absorption features at low temperatures, we design and employ the 'no-recoil approximation' in which we assume that the momentum transfer to the spin degrees of freedom can only be Δqs = 0 or Δqs = π/a during an optical excitation We present explicit analytical results for the optical absorption in the presence of a lattice dimerization δ and a nearest-neighbour interaction V for the Néel and dimer state We find that the coherent part of the optical absorption for V = 0 is given by a single peak at ω = U and broad but weak absorption bands for Wδ≤|ω - U|≤W. The central peak at ω = U vanishes only for δ = 0 in the Néel state. For an appreciable nearest-neighbour interaction V > W/2, almost all spectral weight is transferred to the Δqc = 0 exciton and the Δqc = π/a exciton, whose relative spectral weights depend very sensitively on both the lattice and the spin dimerization of the ground state.

UR - http://www.scopus.com/inward/record.url?scp=0002353348&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0002353348&partnerID=8YFLogxK

M3 - Article

VL - 75

SP - 47

EP - 65

JO - Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties

JF - Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties

SN - 1364-2812

IS - 1

ER -