The isotope effect in the Hubbard model with local phonons

Abstract

The isotope effect (IE) in the two-dimensional Hubbard model with Holstein phonons is studied using the dynamical cluster approximation with quantum Monte Carlo. At small electron-phonon (EP) coupling the IE is negligible. For larger EP coupling there is a large and positive IE on the superconducting temperature that decreases with increasing doping. A significant IE also appears in the low-energy density of states, kinetic energy and charge excitation spectrum. A negligible IE is found in the pseudogap and antiferromagnetic (AF) properties at small doping whereas the AF susceptibility at intermediate doping increases with decreasing phonon frequency ${\omega }_0$. This IE stems from increased polaronic effects with decreasing ${\omega }_0$. A larger IE at smaller doping occurs due to stronger polaronic effects determined by the interplay of the EP interaction with stronger AF correlations. The IE of the Hubbard-Holstein model exhibits many similarities with the IE measured in cuprate superconductors.

References in corpus (15)

• Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors
• Quantum Cluster Theories
• Nonlocal Dynamical Correlations of Strongly Interacting Electron Systems
• The Dynamical Cluster Approximation: Non-Local Dynamics of Correlated Electron Systems
• An unusual isotope effect in a high-transition-temperature superconductor
• A Quantum Monte Carlo algorithm for non-local corrections to the Dynamical Mean-Field Approximation
• Direct observation of the oxygen isotope effect on the in-plane magnetic field penetration depth in optimally doped YBa${}_2$Cu${}_3$O${}_{7-\delta }$
• An Isotopic Fingerprint of Electron-Phonon Coupling in High-Tc Cuprates
• Oxygen isotope effect on the in-plane penetration depth in underdoped La_{2-x}Sr_{x}CuO_{4} single crystals
• Phase Diagram of the Hubbard Model: Beyond the Dynamical Mean Field
• Unconventional isotope effects in the high-temperature cuprate superconductors
• Synergistic Polaron Formation in the Hubbard-Holstein Model at Small Doping
• Oxygen-isotope effect on the in-plane penetration depth in cuprate superconductors
• Isotope effects in underdoped cuprate superconductors: a quantum phenomenon
• Isotope effects and possible pairing mechanism in optimally doped cuprate superconductors

Cited by in corpus (11)

• Intermediate Coupling Model of the Cuprates
• Optical model-solution to the competition between a pseudogap phase and a Mott-gap phase in high-temperature cuprate superconductors
• On the theory of superconductivity in the extended Hubbard model: Spin-fluctuation pairing
• Spin fluctuations and high-temperature superconductivity in cuprates
• Phonon enhancement of electronic orders and negative isotope effect in the Hubbard-Holstein model on a square lattice
• Quantum Criticality and Incipient Phase Separation in the Thermodynamic Properties of the Hubbard Model
• Large isotope effect on $T_c$ in cuprates despite of a small electron-phonon coupling
• Suppression of superconductivity in the Hubbard model by buckling and breathing phonons
• Isotope effect on the superconducting critical temperature of cuprates in the presence of charge order
• Anomalous isotope Effect in d-wave superconductors on the square lattice
• Microscopic theory of high-temperature superconductivity in strongly correlated electronic systems