Doublon-holon pairing mechanism via exchange interaction in two-dimensional cuprate Mott insulators

Terashige, T.; Ono, Tetsu; Miyamoto, T.; Morimoto, Takeshi; Yamakawa, Hisashi; Kida, N.; Ito, T.; Sasagawa, T.; Tohyama, Takami; Okamoto, Hiroshi

doi:10.1126/sciadv.aav2187

Cited by 27 publications

(21 citation statements)

References 48 publications

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“…The mechanism underlying the exciton formation in this work is different from Ref. 39, which observed nearest-neighbor doublon-holon pairs in an antiferromagnetic background that are bound via the spin-spin interaction J ex . In our system, J ex ≈ 4t 2 h U = 0.16 is much smaller than the values of V considered.…”

Section: Discussioncontrasting

confidence: 71%

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Photoenhanced excitonic correlations in a Mott insulator with nonlocal interactions

et al. 2020

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We investigate the effect of nonlocal interactions on the photo-doped Mott insulating state of the twodimensional Hubbard model using a nonequilibrium generalization of the dynamical cluster approximation. In particular, we compare the situation where the excitonic states are lying within the continuum of doublonholon excitations to a set-up where the excitons appear within the Mott gap. In the first case, the creation of nearest-neighbor doublon-holon pairs by excitations across the Mott gap results in enhanced excitonic correlations, but these excitons quickly decay into uncorrelated doublons and holons. In the second case, photoexcitation results in long-lived excitonic states. While in a low-temperature equilibrium state, excitonic features are usually not evident in single-particle observables such as the photoemission spectrum, we show that the photo-excited nonequilibrium system can exhibit in-gap states associated with the excitons. The comparison with exact-diagonalization results for small clusters allows us to identify the signatures of the excitons in the photo-emission spectrum.

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Section: Discussioncontrasting

confidence: 71%

“…Excitons may play a role in several recent experiments on photo-doped Mott insulators [3,39]. The mechanism underlying the exciton formation in this work is different from Ref.…”

Section: Discussionmentioning

confidence: 70%

Photoenhanced excitonic correlations in a Mott insulator with nonlocal interactions

et al. 2020

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“…In Fig. 4, we show U -dependence of Reσ(ω) for the two-dimensional Hubbard model with (L x , L y ) = (6,6). For U ≥ 7, we find the formation of an excitonic peak at the edge of the Mott gap.…”

Section: B Optical Conductivity For Two-dimensional Systemsmentioning

confidence: 89%

Density-matrix renormalization group study of optical conductivity of the Mott insulator for two-dimensional clusters

Shinjo,

Tamaki,

Sota

et al. 2021

Preprint

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The real part of optical conductivity, Reσ(ω), of the Mott insulators has a large amount of information on how spin and charge degrees of freedom interact with each other. By using the timedependent density-matrix renormalization group, we study Reσ(ω) of the two-dimensional Hubbard model on a square lattice at half filling. We find an excitonic peak at the Mott-gap edge of Reσ(ω) not only for the two-dimensional square lattice but also for two-and four-leg ladders. For the square lattice, however, we do not clearly find a gap between an excitonic peak and continuum band, which indicates that a bound state is not well-defined. The emergence of an excitonic peak in Reσ(ω) implies the formation of a spin polaron. Examining the dependence of Reσ(ω) on the on-site Coulomb interaction and next-nearest neighbor hoppings, we confirm that an excitonic peak is generated from a magnetic effect. Electron scattering due to an electron-phonon interaction is expected to easily suppress an excitonic peak since spectral width of an excitonic peak is very narrow. Introducing a large broadening in Reσ(ω) by modeling the electron-phonon coupling present in La2CuO4 and Nd2CuO4, we obtain Reσ(ω) comparable with experiments.

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“…The salience of e-ph coupling in the real material (absent in DMFT treatments mentioned above) suggests an alternative, intuitive interpretation for the narrow peaks as polaronic bound states. Excess electrons injected into a Mott insulator (doublons) can in principle interact with other excitations to form bound states (see for example [46]). In this case, the charge of the additional electron may be partially screened by the ionic displacement associated with lattice distortions (phonons), reducing the on-site repulsion U and allowing the bound state to split off from the UHB.…”

Section: Discussionmentioning

confidence: 99%

Doublon-like excitations and their phononic coupling in a Mott charge-density-wave system

Butler,

Yoshida,

Hanaguri

et al. 2021

Preprint

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Electron-phonon-driven charge density waves can in some circumstances allow electronic correlations to become predominant, driving a system into a Mott insulating state. New insights into both the Mott state and preceding charge density wave may result from observations of the coupled dynamics of their underlying degrees of freedom. Here, tunneling injection of single electrons into the upper Hubbard band of the Mott charge-density-wave material 1T -TaS2 reveals extraordinarily narrow electronic excitations which couple to amplitude mode phonons associated with the charge density wave's periodic lattice distortion. This gives a vivid microscopic view of the interplay between excitations of the Mott state and the lattice dynamics of its charge density wave precursor.

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Doublon-holon pairing mechanism via exchange interaction in two-dimensional cuprate Mott insulators

Cited by 27 publications

References 48 publications

Photoenhanced excitonic correlations in a Mott insulator with nonlocal interactions

Photoenhanced excitonic correlations in a Mott insulator with nonlocal interactions

Density-matrix renormalization group study of optical conductivity of the Mott insulator for two-dimensional clusters

Doublon-like excitations and their phononic coupling in a Mott charge-density-wave system

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