THz-Frequency Modulation of the Hubbard<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>U</mml:mi></mml:math>in an Organic Mott Insulator

Singla, Rashmi; Cotugno, Giovanni; Kaiser, Stefan; Först, Michael; Mitrano, Matteo; Liu, Haiyun; Cartella, Andrea; Manzoni, Cristian; Okamoto, Hiroshi; Hasegawa, Tatsuo; Clark, Stephen R. L.; Jaksch, Dieter; Cavalleri, Andrea

doi:10.1103/physrevlett.115.187401

Cited by 84 publications

(87 citation statements)

References 38 publications

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“…The amplitude of the modulation of the T 1u mode quoted in Ref. 41 and used in the present work is but an order of magnitude estimate, and a more precise ab-initio determination is desirable (as well as a direct experimental determination of the transient modulation of the structure). The light excitation may also induce other relevant changes in the material besides the interaction imbalance considered here, such as more complex changes in the band-structure, a modulation of the inter-orbital Coulomb matrix element and even a direct modulation of the inverted effective Hund's coupling (due e.g.…”

Section: Discussionmentioning

confidence: 85%

Enhancing superconductivity inA3C60fullerides

et al. 2016

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Motivated by the recent experimental report of a possible light-induced superconductivity in K3C60 at high temperature [Mitrano et al., Nature 530, 451 (2016)], we investigate theoretical mechanisms for enhanced superconductivity in A3C60 fullerenes. We find that an 'interaction imbalance' corresponding to a smaller value of the Coulomb matrix element for two of the molecular orbitals in comparison to the third one, efficiently enhances superconductivity. Furthermore, we perform firstprinciple calculations of the changes in the electronic structure and in the screened Coulomb matrix elements of K3C60 , brought in by the deformation associated with the pumped T1u intra-molecular mode. We find that an interaction imbalance is indeed induced, with a favorable sign and magnitude for superconductivity enhancement. The physical mechanism responsible for this enhancement consists in a stabilisation of the intra-molecular states containing a singlet pair, while preserving the orbital fluctuations allowing for a coherent inter-orbital delocalization of the pair. Other perturbations have also been considered and found to be detrimental to superconductivity. The light-induced deformation and ensuing interaction imbalance is shown to bring superconductivity further into the strong-coupling regime.

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Section: Discussionmentioning

confidence: 85%

Enhancing superconductivity inA3C60fullerides

et al. 2016

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“…The system Hamiltonian H sys (t) consists of the unperturbed part H sys,0 and the external periodic field H ext (t). Here, we focus on a simple but relevant example of an electron-phonon coupled system, the Holstein model, with the Hamiltonian (2) where c † i is the creation operator for an electron with spin σ at site i, v is the electron hopping, μ is the electron chemical potential, n i = c another phonon mode (Raman mode) that is linearly coupled to the electron sector [11,36] or through a nonlinear-coupling mechanism [8,13,37]. Our present interest is in the former case.…”

Section: Modelmentioning

confidence: 99%

Nonequilibrium steady states and transient dynamics of conventional superconductors under phonon driving

Murakami¹,

Tsuji²,

Eckstein³

et al. 2017

Phys. Rev. B

154

138

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We perform a systematic analysis of the influence of phonon driving on the superconducting Holstein model coupled to heat baths by studying both the transient dynamics and the nonequilibrium steady state (NESS) in the weak and strong electron-phonon coupling regimes. Our study is based on the nonequilibrium dynamical mean-field theory, and for the NESS we present a Floquet formulation adapted to electron-phonon systems. The analysis of the phonon propagator suggests that the effective attractive interaction can be strongly enhanced in a parametric resonant regime because of the Floquet side bands of phonons. While this may be expected to enhance the superconductivity (SC), our fully self-consistent calculations, which include the effects of heating and nonthermal distributions, show that the parametric phonon driving generically results in a suppression or complete melting of the SC order. In the strong coupling regime, the NESS always shows a suppression of the SC gap, the SC order parameter, and the superfluid density as a result of the driving, and this tendency is most prominent at the parametric resonance. Using the real-time nonequilibrium DMFT formalism, we also study the dynamics towards the NESS, which shows that the heating effect dominates the transient dynamics, and SC is weakened by the external driving, in particular at the parametric resonance. In the weak coupling regime, we find that the SC fluctuations above the transition temperature are generally weakened under the driving. The strongest suppression occurs again around the parametric resonances because of the efficient energy absorption.

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“…The pulse duration of visible radiation, which can be in the range of 4-40 fs, also enables indirect access to resonant modes in the infrared spectral range such as coherent phonons and Raman active modes [64,65]. Additionally, ultra short light pulses can be used for sub-cycle interrogation of processes excited with carrier envelope phase stable mid-IR [66] and THz pulses [55]. We stress that the efficient background suppression afforded by TrpHD with pulsed laser sources may find use in a wide array of spectroscopic measurements in addition to time-resolved control and interrogation of matter at the nanoscale.…”

Section: Outlook and Conclusionmentioning

confidence: 99%

Artifact free time resolved near-field spectroscopy

et al. 2017

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Abstract:We report on the first implementation of ultrafast near field measurements carried out with the transient pseudoheterodyne detection method (Tr-pHD). This method is well suited for efficient and artifact free pump-probe scattering-type near-field optical microscopy with nanometer scale resolution. The Tr-pHD technique is critically compared to other data acquisition methods and found to offer significant advantages. Experimental evidence for the advantages of Tr-pHD is provided in the near-IR frequency range. Crucial factors involved in achieving proper performance of the Tr-pHD method with pulsed laser sources are analyzed and detailed in this work. We applied this novel method to femtosecond time-resolved and nanometer spatially resolved studies of the photo-induced effects in the insulator-to-metal transition system vanadium dioxide. 5660-5694 (2000). 4. T. Kampfrath, K. Tanaka, and K. A. Nelson, "Resonant and nonresonant control over matter and light by intense terahertz transients," Nat. Photonics 7(9), 680-690 (2013). 5. J. Orenstein, "Ultrafast spectroscopy of quantum materials," Phys. Today 65(9), 44-50 (2012 Express ; 25 (2017 25 ( ), 23. -S. 28589-28611 https://dx.doi.org/10.1364 Cavalleri, "Light-Induced Superconductivity in a Stripe-Ordered Cuprate," Science 331(6014), 189-191 (2011). 12. J. Zhang, X. Tan

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THz-Frequency Modulation of the HubbardUin an Organic Mott Insulator

Cited by 84 publications

References 38 publications

Enhancing superconductivity inA3C60fullerides

Enhancing superconductivity inA3C60fullerides

Nonequilibrium steady states and transient dynamics of conventional superconductors under phonon driving

Artifact free time resolved near-field spectroscopy

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