PI: Thomas Maier
Quantum Monte Carlo simulations of a two-dimensional Hubbard model reveal that the combined effects of a decreasing spin-fluctuation pairing interaction and weak impurity scattering lead to the abrupt overdoped end of the superconducting dome in the cuprate materials. These results provide new insight into the nature of the pairing mechanism that leads to high-temperature superconductivity.
The two-dimensional Hubbard model is commonly believed to contain the key ingredients to describe high-temperature superconductivity, but accurate solutions have remained elusive due to its exponential complexity. The dynamic cluster approximation (DCA) quantum Monte Carlo method offers a powerful tool to study its superconducting behavior using high-end computing. The support for ASCR funded researchers provided by this SciDAC partnership led to significant acceleration and runtime improvements (up to 15 x) of the DCA++ code that implements the DCA method on ORNL’s Summit supercomputer. These improvements were enabled by extensive profiling including the TAU tool of the RAPIDS SciDAC institute and have provided the capability to study the Hubbard model with unprecedented accuracy in parameter regions not accessible before, which has enabled this scientific advance. In the future, even more accurate calculations will be performed on models that include additional degrees of freedom and thus allow for the study of materials specific behavior that is not possible in the simple single-band Hubbard model.
Related Publication:
T. A. Maier, S. Karakuzu, and D. J. Scalapino, The overdoped end of the cuprate phase diagram, submitted to Physical Review Letters (2020).
