Enhancement of superexchange pairing in the periodically driven Hubbard model

J. R. Coulthard, S. R. Clark, S. Al-Assam, A. Cavalleri, and D. Jaksch
Phys. Rev. B 96, 085104 – Published 1 August 2017

Abstract

Recent experiments performed on cuprates and alkali-doped fullerides have demonstrated that key signatures of superconductivity can be induced above the equilibrium critical temperature by optical modulation. These observations in disparate physical systems may indicate a general underlying mechanism. Multiple theories have been proposed, but these either consider specific features, such as competing instabilities, or focus on conventional BCS-type superconductivity. Here we show that periodic driving can enhance electron pairing in strongly correlated systems. Focusing on the strongly repulsive limit of the doped Hubbard model, we investigate in-gap, spatially inhomogeneous, on-site modulations. We demonstrate that such modulations substantially reduce electronic hopping, while simultaneously sustaining superexchange interactions and pair hopping via driving-induced virtual charge excitations. We calculate real-time dynamics for the one-dimensional case, starting from zero- and finite-temperature initial states, and we show that enhanced singlet-pair correlations emerge quickly and robustly in the out-of-equilibrium many-body state. Our results reveal a fundamental pairing mechanism that might underpin optically induced superconductivity in some strongly correlated quantum materials.

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  • Received 13 September 2016
  • Revised 25 May 2017

DOI:https://doi.org/10.1103/PhysRevB.96.085104

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsAtomic, Molecular & Optical

Authors & Affiliations

J. R. Coulthard1, S. R. Clark2,3, S. Al-Assam1, A. Cavalleri1,3, and D. Jaksch1,4

  • 1Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
  • 2Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
  • 3Max Planck Institute for the Structure and Dynamics of Matter, University of Hamburg CFEL, Hamburg, Germany
  • 4Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543

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Issue

Vol. 96, Iss. 8 — 15 August 2017

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