Isotope effect on the superconducting critical temperature of cuprates in the presence of charge order

Abstract

Using the large-$N$ limit of the $t$-$J$ model and allowing also for phonons and the electron-phonon interaction we study the isotope effect $\alpha$ for coupling constants appropriate for YBCO. We find that $\alpha$ has a minimum at optimal doping and increases strongly (slightly) towards the underdoped (overdoped) region. Using values for the electron phonon interaction from the local density approximation we get good agreement for $\alpha$ as a function of $T_c$ and doping $\delta$ with recent experimental data in YBCO. Our results strongly suggest that the large increase of $\alpha$ in the underdoped region is (a) caused by the shift of electronic spectral density from low to high energies associated with a competing phase (in our case a charge density wave) and the formation of a gap, and (b) compatible with the small electron phonon coupling constants obtained from the local density approximation. We propose a similar explanation for the anomalous behavior of $\alpha$ in Sr doped La${}_2$CuO${}_4$ near the doping 1/8.

14 pages, 6 figures

References in corpus (8)

• Two Gaps Make a High Temperature Superconductor?
• Giant phonon anomalies and central peak due to charge density wave formation in YBa${}_2$Cu${}_3$O${}_{6.6}$
• Photoemission kinks and phonons in cuprates
• Momentum dependence of the electron-phonon coupling and self-energy effects in YBa_2Cu_3O_7 within the local density approximation
• Synergistic Polaron Formation in the Hubbard-Holstein Model at Small Doping
• Quantitative Determination of Eliashberg Function and Evidence of Strong Electron Coupling with Multiple Phonon Modes in Heavily Over doped (Bi,Pb)2Sr2CuO6
• The isotope effect in the Hubbard model with local phonons
• Absence of the 1/8 -anomaly in oxygen isotope effect on YBa${}_2$Cu${}_3$O${}_y$

Cited by in corpus (4)

• Unconventional Superconductivity
• Dual parquet scheme for the two-dimensional Hubbard model: modelling low-energy physics of high-$T_c$ cuprates with high momentum resolution
• Interplay of magnetism and superconductivity in 2D extended Hubbard model
• Anomalous isotope Effect in d-wave superconductors on the square lattice