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Criticality and Superconductivity in the Two-dimensional Hubbard Model of Strongly Correlated Electronic Systems

Khatami, Ehsan
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250711006

Abstract Details

2009, PhD, University of Cincinnati, Arts and Sciences : Physics.
Many properties of the two-dimensional Hubbard model have been explored for the model parameters appropriate for strongly correlated electronic systems, especially cuprate superconductors. Most of the calculations are done using a well-established dynamical cluster quantum Monte Carlo method. Using this method, we investigate the effect of long-range hoppings on superconductivity with and without the presence of phonons on small clusters. The superconducting transition temperature, Tc, is found to generally decrease with a negative next nearest neighbor hopping, t′. In the presence of the Holstein phonons, a finite t′ enhances Tc in the under-doped region for the hole-doped system, consistent with band structure calculations and experiment. The validity of the spin-susceptibility-mediated pairing in this model is studied and found to yield symmetries other than d-wave when a finite t′ is considered. A new numerical algorithm for solving the embedded cluster problems is introduced, and used to calculate the thermodynamic properties of the model on larger clusters, especially those associated with the quantum critical behavior at finite doping. Our results suggest that the quantum critical point (QCP) which separates the Fermi liquid and pseudogap regions, is the second order terminus of the line of first order phase separation transition in the limit when a positive t′ goes to zero. For small t′, the superconducting dome is centered at the QCP, suggesting that charge fluctuations might have a role in the pairing mechanism in this model.
Michael Ma (Committee Chair)
phonons; Hubbard Model; e¿¿¿¿¿¿¿ect; DQMC; hoppings

Recommended Citations

Citations

  • Khatami, E. (2009). Criticality and Superconductivity in the Two-dimensional Hubbard Model of Strongly Correlated Electronic Systems [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250711006

    APA Style (7th edition)

  • Khatami, Ehsan. Criticality and Superconductivity in the Two-dimensional Hubbard Model of Strongly Correlated Electronic Systems. 2009. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250711006.

    MLA Style (8th edition)

  • Khatami, Ehsan. "Criticality and Superconductivity in the Two-dimensional Hubbard Model of Strongly Correlated Electronic Systems." Doctoral dissertation, University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250711006

    Chicago Manual of Style (17th edition)

ucin1250711006
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© 2009, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.