Abstract

We study the superconducting pairing correlations in the ground state of the doped Hubbard model -- in its original form without hopping beyond nearest neighbor or other perturbing parameters -- in two dimensions at intermediate to strong coupling and near optimal doping. The nature of such correlations has been a central question ever since the discovery of cuprate high-temperature superconductors. Despite unprecedented effort and tremendous progress in understanding the properties of this fundamental model, a definitive answer to whether the ground state is superconducting in the parameter regime most relevant to cuprates has proved exceedingly difficult to establish. In this work, we employ two complementary, state-of-the-art many-body computational methods, constrained path (CP) auxiliary-field quantum Monte Carlo (AFQMC) and density matrix renormalization group (DMRG) methods, deploying the most recent algorithmic advances in each. Systematic and detailed comparisons between the two methods are performed. The DMRG is extremely reliable on small width cylinders, where we use it to validate the AFQMC. The AFQMC is then used to study wide systems as well as fully periodic systems, to establish that we have reached the thermodynamic limit. The ground state is found to be non-superconducting in the moderate to strong coupling regime in the vicinity of optimal hole doping.

Highlights

  • Understanding high-temperature superconductivity in the cuprates [1] has been a long-standing mystery and one of the greatest challenges in theoretical condensed matter physics [2]

  • We study pairing correlations and superconductivity using two complementary methods—the density matrix renormalization group (DMRG) and auxiliary-field quantum Monte Carlo (AFQMC) methods

  • The order parameter is computed in AFQMC after a particlehole transformation has been applied to Eq (1), which results in a modified Hamiltonian that conserves the total particle number [36] but breaks total Sz

Read more

Summary

INTRODUCTION

Understanding high-temperature superconductivity in the cuprates [1] has been a long-standing mystery and one of the greatest challenges in theoretical condensed matter physics [2]. Larger systems are needed to properly allow stripes and superconductivity to compete or coexist.) Hopping parameters t0 and third neighbor (diagonal) t00 have been predicted using electronic structure methods [58]; even small differences in these parameters can alter the ground-state phase, and it is difficult to establish whether additional terms, such as hopping mediated by a second hole, are important. It is not clear whether one needs to study a three-band model in order to connect directly with the cuprates.

APPROACH
Two complementary methods
Constrained-path auxiliary-field quantum Monte Carlo
Density matrix renormalization group
Two different ways to characterize superconducting correlation
Pairing order parameter
Pair-pair correlation function
Competition between pairing and stripes
RESULTS
Competition between stripe and superconducting orders
SUMMARY AND PERSPECTIVE
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call