Research Experiences for Undergraduates in Computational Methods with Applications in Materials Science
Major
Physics
College
College of Arts and Sciences
Research Mentor
Rudolf Torsten Clay
Research Mentor's Department
Department of Physics and Astronomy
Research Center
Center for Computational Sciences
Abstract
Poster created as part of the Center for Computational Sciences' Research Experiences for Undergraduates in Computational Methods with Applications in Materials Science and presented at the 2024 Undergraduate Research Showcase.
The globally accepted Bardeen-Cooper-Schrieffer (BCS) theory explains the pairing mechanism in low-temperature elemental superconductors but fails to explain pairing in high critical temperature superconductors. Unconventional superconductors with higher critical temperatures require moreexotic pairing mechanisms considering electron-electron interactions, such as spin-fluctuated-mediated pairing. Many-body calculations within the Hubbard model, which includes short-range electron-electron repulsion, have shown that superconducting pair correlations are enhanced when the density of carriers is close to one-half per orbital, a characteristic density in many unconventional superconductors. However, questions related to the accuracy of previous calculations remain. In this work, we employed a more accurate numerical method, Self-Consistent Constrained Path Quantum Monte Carlo (SC-CPMC), to check the accuracy of CPMC calculations without the self-consistent optimization of the trial wavefunction. By eliminating the artificial lattice symmetry breaking previously used, we restored the intrinsic symmetry of the lattice. This study also investigated effects of a larger Hubbard U. Our results confirm that the Hubbard U significantly enhancessuperconducting pair-pair correlations for carrier densities close to 0.5 per site.
Presentation Date
Summer 8-2-2024
Keywords
superconductivity, Quantum Monte Carlo, computational physics
Recommended Citation
Padvorac, Jeremy and Clay, Rudolf Torsten, "Repulsive Coulomb interactions enhance Superconductivity Selectively at Density 0.5 per site" (2024). Research Experiences for Undergraduates in Computational Methods with Applications in Materials Science. 4.
https://scholarsjunction.msstate.edu/ccs-reu/4